Okay, I just want to clarify this--is there a perception here that the Bantustan system was to some substantial degree about the self-determination and self-development of the African tribal peoples?
Are you serious? That's a "yes" to my question above I guess.
Could some bantustans specialize in low-tech industries, creating sweat-shops and maquiladoras with South-African companies, to make money, since, in most cases, the soil was too poor to do much?
Again, seriously? You are seeing the Nationalists setting up the Bantustans as captive, dependent so-called autonomous states that have no choice but to either starve or prostitute themselves in this way as some sort of win-win?
Or just cold-bloodedly answering an abstract challenge of how evil can prosper?
The OTL plan was that the "maquiladoras" would be on RSA soil so that it would be white owned companies that would make the profits; the "citizens" of the Bantustans would get nothing but wages, and have the status of aliens in the Republic that would appropriate all the wealth except whatever was doled out in wages. The Bantustans would bear all the responsibility of all social welfare of their subjects, and realistically there would be no effective democracy in any of them since the Bantustan leaders would be hand-picked and supervised, if not by legal channels than informally, by the presumably still Nationalist controlled RSA white regime. OTL there was a lot of corruption in them, since the supposedly tribal elected or appointed leaders would in fact owe their power and privileges to gratifying RSA people, not their own.
Now why on Earth would the Nationalists consider taking their hands off the controls and handing real power and real wealth over to these puppet states?
And how could the Bantustans practically have real independence if they don't collectively get a big share of the collective national wealth of South Africa?
Apartheid meant "separate development" of the various ethnic communities.
Apartheid means segregation. It means the Whites of South Africa, an identity the Nationalist Party felt free to define and govern no matter what people who happened to be of pure European extraction themselves might want to offer as dissents, affirm that mixing with people of other races is dangerous and unhealthy. The ship of "separate development" sailed centuries ago when the various European powers--first the Dutch/French Huguenot derived Afrikaners and then the British--each overwhelmed native African peoples, appropriated whatever land they wanted, reorganized the work force with formal slavery and later forms of dependency as closely tantamount to slavery as relations of legally free African-American slaves in the USA under Jim Crow were, appropriated the lion's share of all profits, and now at this late date want to say "all that wealth is ours, the best land is ours, here, go make something of yourself on this scanty reservation we give you." How is this "separate development?"
To be sure if they were to be sincere and consistent, then the Bantustan peoples would perhaps be left alone to develop, from this scanty pittance, as they wish without the RSA interfering. But do you honestly believe this would be allowed to happen, if a predictable interest of the peoples crowded so densely with so little would be to break the bonds, and appropriate a much larger and more desirable share of South Africa's land and infrastructure for themselves? South African security would demand interference, to make sure there is no possibility of such self-interested development.
Which internal contradictions of apartheid you'd deem inherent and fundamental?
Perhaps no internal contradictions at all. If the Whites (again, not necessarily all South Africans of European extraction, just the ones accepting Nationalist positions as their own) were to hand over a fair share of the wealth and infrastructure and land to the majority of the inhabitants, and then take their hands off and make do with a mere 10 percent or so of South Africa's pre-self-dismembership resources, closing their eyes to everything happening in their internal neighbors, perhaps there is no contradiction, merely the consistent and frank affirmation of the claim that the different races simply cannot work together. Which I think is absurd and morally outrageous, but it would be consistent. Also brutal of course.
But less brutal than what they really meant to do and actually did. The intended and partially accomplished crowding of the majority of South Africa's people on far too small and poor shares of land, broken up into absurdly discontinuous fragments in at least one case I know of because the regime did not have the gumption to impose any sacrifices on any subset of the Whites who benefited and therefore could not relocate them and concede a portion of good land; the consistent arrangement for the necessary labor sites for the pent-up tribal peoples to be forced by circumstances to work in white-owned capacities on RSA soil, all demonstrated that in fact South Africa had evolved with tremendous intertwining of all the various racial categories the government so zealously defined and policed. To declare that different peoples should not mix and unmix them seems deplorable and quixotic, but the actual plan OTL actually did no such thing, merely substituted a new pretext to police people of non-white race for the old ones. But it did not foresee actually disentangling their affairs at all, merely washed the hands of the White state of any responsibility for people that it would in fact seek to continue to control, and exploit. That's contradictory!
So you ask, "how could it be that the Bantustans are set up to be genuinely independent?" And I have answered--they'd need orders of magnitude higher shares of the wealth of the Republic, so much so that if one did not (as I, admittedly deviating from the premise quite a bit) first separate out people who would be willing to repudiate the Nationalist program of apartheid in all forms and make a go of a comprehensive republic not based on legal caste hierarchy, with all having equal rights and the discretion to associate as they pleased, then it would follow that all the separate categories of each race, including the mixed-race people and Asians, would each need to be assigned homelands. The Republic of South Africa would cease to exist, replaced by a Balkanized patchwork of little countries. The whole premise of Nationalism was that these diverse peoples cannot cooperate, so an effective confederation for purposes such as mutual self-defense would be out. Whites too would have to suffer the majority of themselves being uprooted from homes they had lived in in some cases for centuries and be moved into a Bantustan of their own (or two or more of them, separating Afrikaners from English speakers). It would be massively disruptive and leave the racially purified fragments, all of them, including the new White homelands, so small that none of them are very viable anymore. Whites, and Africans, and Coloureds, and Asians, who individually disagreed with the Nationalist line that cooperation and cosmopolitan mixing was unworkable and bad would be overruled and faced with a choice of either accepting their assigned place in the purified nation the government's racial accounting allocated them to, or exile themselves from South Africa completely. I therefore suggested that people willing to make an attempt at mixed unification become the default inheritors of the remnant matrix surrounding all the purified homelands and embedding them in South Africa proper. Guessing that these would be something between a quarter and 2/3 the total population, such an inclusive Republic could reasonably be the neutral territory each of the separatist nationalities can travel through for access to the larger world.
What the Nationalists actually wanted to do was handle the largest single category of non-Whites, the African natives who retained their old identity, by subdividing them, assigning them small reservations that confined them and divided them against each other, and thus make the job of running a white supremacist Republic ruling over all remaining non-white categories and exploiting them, while retaining de facto control over the allegedly independent African peoples trapped and helpless as well. They made themselves the default, treated themselves as a special category ruling all the rest and setting the rules for all. For what reason should they wish to trade that advantageous "solution" for a fair and unprofitable shattering of South Africa into many separate countries?
And of course quite aside from the moral outrage that such a triumph of racist pig-headedness would represent, even if done with fairness regarding the apportionment of resources to each group, it would be a dangerous and unstable situation, as the broadly similar shattering of Yugoslavia in the 1990s demonstrated. Having been divided into invidious little groups, what is to stop any number of them from seeking to improve its fortunes by right of conquest at the expense of neighbors the Nationalist ideology claimed they had no common bond with? The choices would be, principled (if on a repulsive principle) and fair separation of all from all, followed by ruthless and mutually ruinous warfare, or for some overarching organization to exist. The Nationalists held that that could hardly be a federation since their whole premise was the inability of the diverse races to cooperate, therefore they reserved this role for themselves, kingmakers for the whole region and subject to no reciprocal accountability themselves.
If we attempt to pretend that the whole thing was not merely and essentially a cynical reconfiguration of white rule and exploitation, but had some higher principle that would be followed by all, it clearly becomes dysfunctional.
In order to enforce fairness in the division of national wealth if this great divorce were to go forward, it would be necessary for the Nationalists to be defeated politically anyway. With them defeated, the much superior idea that the peoples of South Africa had in fact been entangled with each other by history and therefore should unite as equal individuals under the law, with universal and equal rights, and let individuals decide for themselves how much association with others they wished to pursue versus locating in blocks to live with their own kind as they perceived it, would have a way forward. All forms of apartheid, Grand or otherwise, should have been discarded and eventually were OTL, at any rate as legally sanctified rules imposed by the law. This has always been the way forward for South Africa, with the doctrine of racial separation exposed for the evil it has always been.