You did not have to go as far as USA to see that. Trip to western Berlin would be enough. Countries that got under USA sphere of influence had it much better. They got lots of money with Marshall's plan to rebuild economies after war.
So even if they would knew there is a better life it was all decided at Jalta and they were most likely not able to do anything about it without straight out starting new war against Soviets running things in the east. Unfortunately scratching out a living was their destiny.
Except those in the "USA sphere" that had pro-US dictators forced upon them - like Chile, Argentina, Guatemala, Indonesia, etc. - even Spain, Portugal, South Korea, Taiwan and Brazil suffered greatly under US-supported (to varying degrees) dictatorships.
Except that, materially, those in the "USA sphere" -- even those with pro-US dictators forced upon them -- are better off comparatively than their neighbours or a comparable country.
Just to look at the countries you listed and their GDP per capita:
1) Asia
Taiwan vs Mainland China
South Korea vs North Korea
Indonesia (under Suharto) vs Indonesia (under Sukarno)
2) Europe
Spain & Portugal vs Eastern European countries
(These two are weird. They were originally old facist countries that stayed neutral during WWII. They were also rural and not industrial compared to every other Western European country until recently)
3) South America
Guatemala vs Nicaragua
Brazil vs India (This is tough, since no country can really compare itself to Brazil in South America. I think Indonesia is probably most similar, but they are also on the list. India was more Soviet-aligned)
Argentina & Chile vs every other Spanish-speaking South American country.
It's not all rainbows and sunshine, but everybody struggles to some degree during the cold war. Those that the CIA kept propping up are much much better economically than those that didn't receive US funding and arms.
I can't believe I am defending the CIA in 2023. But here we are.
Most of these countries I have never been in but let's consider Taiwan. I've been there in the 70s. I've had many visits to China since the late 90s. They should have started out pretty much even since 1948. Admittedly, my memories are old but I would say 70s Taiwan was similar to 90s China--something held China back far more than Taiwan was held back.
I have also had a dramatic illustration of the endemic food problems in communist-era China. When I was first in China I could see over the crowds--eye height for me was above the top-of-hair height for virtually all the locals. This was just before the first people born in the capitalist era were coming of age. As they came of age my view got more and more obstructed--these days I'm taller than the average Chinese person but the difference is nowhere near as extreme. That's not genetics, that's nutrition. In other words, virtually everybody was stunted by inadequate nutrition during the communist era. (I can't make the height comparison for Taiwan, I was not an adult at the time.)
Or look at the economic situation in China back then. A discussion that played out again and again. Young female in China, generally a shopkeeper, talking to my wife (China-born, native speaker): "does he [referring to me] understand us?" Her: "no" (I can pick out an occasional word) Woman: "How do you like being married to an American?" Her: "I'm happy" Woman: "How do I get one?", often followed by providing pictures and contact information in the hopes she could play matchmaker. It's been many years since this has happened, though--there isn't the huge economic gap there used to be.
Or lets look at the other second-world countries. I've been in a good portion of them in the 70s. The economic gap was huge, there was also a big gap in how oppressive the government was. I see a lot of people throwing around the term "police state"--almost never with any idea of what that really means. Romania, 1975, we had a run-in with the police. Entirely their goof, their official wrote down the wrong thing and it was pretty easy to show it was their problem. Then came the hard part--they needed some paperwork filled out about the situation. Big problem--we needed translation, nobody was willing to be involved in a police matter even though their name would not appear. Finally a businessman from Austria overheard and offered to help as he knew we wouldn't find a local who was willing. Contrast this with China, IIRC early 2000s: My wife was looking for DVDs of Chinese TV dramas and there were few to be found--DVD sellers almost always only had movies. My wife was a bit naive about how much China had changed resulting in a miscommunication--it didn't occur to her that the "other" stuff he had nearby was porn, not what she was after. (Note: Illegal--almost certainly R18 stuff smuggled in from Hong Kong. There's no way that would have happened in the China she grew up in.) I realize the issue, we walk off but she doesn't make it clear why. The seller keeps pursuing us through the market (someone with an American partner was at the time seen as a lucrative prospect) until a cop shoos him off--and he talks back to the cop. (We did not stick around for the whole exchange, but he was complaining he had done nothing wrong.) That would *never* happen in a police state.
Or lets look at one of those dictatorships that you didn't list: Iran. Once again, 1975. While it was backwards it was a breath of fresh air compared to Pakistan and Afghanistan. (Note: This was before the time of Islamist issues. I wouldn't go back to any of those countries these days!)
So even if they would knew there is a better life it was all decided at Jalta and they were most likely not able to do anything about it without straight out starting new war against Soviets running things in the east. Unfortunately scratching out a living was their destiny.