As a Chilean, I would agree to some extent. Having said that I think the reason most foreigners with little education would prefer Thailand is because It's a country that's made for tourism(Hot weather all year round, beautiful beaches, kinda cheap housing/food as you said, "special" nightlife, etc.). Most countries in South America are not catered towards western expats or tourists as much as Thailand, so in the long term, it would be harder for them to adapt if they don't speak Spanish.
Latin America, in general, is also not nearly as cheap as Thailand(I've been to Argentina, Panama, Brazil, Costa Rica, and Uruguay). I can't talk about Colombia or Ecuador but I would guess that they shouldn't be much cheaper than the countries I mentioned. One of the reasons I travel so much is because it's cheaper for me to travel outside of my country than to vacation in it(even going to Europe or the US can be cheaper than visiting San Pedro de Atacama if you want any decent accommodations these days).
To anyone thinking about moving to Latin America, I would recommend to make some deep research on the real cost of living here(if you want any kind of decent life). Learning Spanish would also help as most people won't speak English outside of Hotels or tourist areas, and they are not expected to do so either.