From all that we've discussed in this post so far, it seems to me that Peron came to power as a result of the mixture of the Latin American political/economic culture in existence in Argentina with the European immigrants (particularly Italian) coming to the country and the Great Depression with all its effects. In other words, when the Italian (and other) immigrants came to Argentina, they were anarchist or syndicalist or what have you, and wanted to integrate themselves there and get full rights, etc. They were put down for a long time by the old conservative elites (representative of at least part of Latin American political culture) that engineered the coup of 1930 in the midst of the Depression, and that paved the way for Peron's popularity among the descendants of European immigrants. Is that a fair way of portraying the lead-on to Peronism, and why Argentina's political development was different than with many other Latin American countries (given that not nearly as many immigrants - particularly Italian - proportionally came to those other countries)?
It's pretty much what, it happened, but remember it weren't the Italians alone. They brought with themselves the ideas of freedom and fighting for their rights, and most of the Argentinean lower classes adopted them. But Anarchism was not important anymore by 1920. Most of them were now either syndicalist or were improving their life quality to become part of the middle class.
The elite paved the way, but it was the depression, the push for answer from the government and the need for a strong leader in who they could trust and put their hope. Like their fathers did 30 years before with Yrigoyen.
If that's so, then even a scenario where Yrigoyen is dead sooner or where Ortiz is president for longer may merely buy some time in terms of avoiding a coup or what not - by a few to several years. Then, Argentina would have perhaps developed much like OTL anyway - who knows?
Not necesarily. A coup could be avoided if Yrigoyen was not elected. Alvear was a peacemaker and was in good terms with almost everybody. Remember he was elite and when Radicalism divided itself, he grouped with the rest of the elite. In a scenario where Alvear is the leader of a united UCR and he puts in power a candidate like him or who he can control, then the coup could very well be prevented. Ortiz is an option for a 1928 to 1934 president.
And Ortiz was a strong and good president except for his health. He was one of Alvear boys, and a very good way to prevent a coup would be to participate in the war. Suppose he enters in 1941 the same time as Brazil and very risked because of the pro Fascist groups in the military. He apeases them by giving them more funds and promising to see action in Europe, which many soldiers want. Anyway, once they enter the war, the pro fascist can't coup the goverment. It would have too strong support from the people and also from the allies. And most of the soldiers would oppose.
After the war, Argentina is more developed, and with strong anti-autoritarism sentiment. So a coup would be very difficult as long as no president starts doing stupid things, and 20 years after the war, impossible.
In addition to what has been said, I would point out that a good way to improve the fortunes of Argentina is to keep Banda Oriental (AKA Uruguay). Retaining a second major port outlet in Montevideo would substantially diminish the Buenos Aires - interior provinces dualism that early Argentina suffered, and make its 19th nation-building less troublesome.
I mentioned this before. As a port, Montevideo has the advantage to be a better natural port, and easy to access from the Parana and Uruguay rivers. This is better in the short term, which is great to complete national unity and prevent a civil war.
But in the long term, Buenos Aires dominates anyway. When railroads come, Montevideo will loose it's importance. Most of the provinces don't have a good water connection to the sea. So their only possible choice is Buenos Aires. And the city is the gateway to Patagonia and the Pampas.
To have a better-off Argentina since this thread is in post-1900, my lists of PODs would be:
Shorter WWI or being butterflied away.
No Great Depression.
Difficult, but anyway the great depression was needed. The primary exports system had to be changed sooner or later. It halted long term development.
1930 Coup never happens, therefore butterflying away Peron from politics.
This has been discussed
Roberto Ortiz never have illness, then political reforms are enacted and enters the WWII.
I explained this above
1943 Coup never happens, thus prevents Peron of taking power.
You have to somehow control the pro Fascist elements in the military. And raising their funds is not an option. They want action, they haven't done nothing important since the early XX Century.
Juan Peron is being defeated by Tamborini in 1946 election.
By this time defeating Peron was very difficult.
Eva Peron remains healthy and runs for vice-presidency.

That's even worse!
1955 Coup fails then Juan Peron consolidates to power, becoming more authoritarian, then 10 to 15 years later, Peronism is being discredited.
Very good one, if all keep going more or less good, today we would be about to re-enter rich and developed countries status.
1962 Coup fails or being butterflied away, thus continuing Frondizi's reform to industrialize Argentina fully.
Another good one, but Peronism will be a problem.
Yes, this coup made the Peronist eager to return to goverment, and gave them more strenght.
Juan Peron never returns in 1973.
Peron would continue to manage politics from exile. But a good propaganda campaing could make Peron look as weak and unable to defend his followers, thus killing Peronism with a headshot.
I don't know. By this time Peronism is part of Argentina, and Peron dying would only make him look as a martyr of autoritarism, even strengthening Peronism.
1976 Coup fails or butterflied away, thus ensuring the democracy to preserved by defeating Isabel Peron in the election by Raul Alfonsin.
One more year with Isabel could do more economic and social damage than the Juntas
No Falkland Wars, thus Junta falls one year earlier.
Could go either way, but the Armed Forces won't be as discredited as OTL, which could be good or bad, tending to the later.
Raul Alfonsin appoints sensible economic advisers.
The Junta destroyed the economy. The crisis was almost inevitable. But he should have carried an industralization program.
Raul Alfonsin succeeds of his plan of transferring the Argentine capital to Viedma and shift to parliamentary system of government.
Absolutely. Two of the evils in the country corrected, a strong executive and the capital in the economic center of the country. How does he manage to get it done? I don't really know. Many important people will be against him.
Carlos Menem never gots the Peronist nomination.
It depends on who gets it.
Carlos Menem never re-elects for a new term.
Something will have to be done with his neoliberal policies
Mexican or Asian economic crisis butterflied away.
I don't know how possible it would be just to butterfly crisis
Carlos Reutemann instead of Nestor Kirchner is the candidate of Eduardo Duhalde for 2003 elections.
Nestor did very good in some areas, and I doubt if Reutemann would have done as good, but at least he won't dominate as much the politics of the country.