Realistically, that is the only viable option. Assuming no conquest, either Britain would effectively puppetise them, or someone else would have to provide their protection. They are too small to be independently defensible, and too rich to be left alone.
I wonder what would happen if the Transvaaal and Oranje merged together and began to emphasize immigration. Though it probably wouldn't change much.
Realistically, that is the only viable option. Assuming no conquest, either Britain would effectively puppetise them, or someone else would have to provide their protection. They are too small to be independently defensible, and too rich to be left alone.
I dunno about no conquest. While I do agree that they are too small to be independently defensible, yet too rich to be left alone, I think Britain would feel they're better off as a colony directly under British administration rather than a client state.
It might, but that would require pretty major changes to their polity. The point to being Boer nations was to preserve their culture. If they'd wanted to be part of a greater, immigration-based society, they could have stayed in British Cape Colony.
The thing is, they'd have to do it early enough. Once the mining rush begins, they will no longer have control over who comes, but before, they might just be able to invite enough people from the right countries. Countries willing to consider taking them under their wing.