Here’s a thought: the very people who rail the most against the restrictions imposed by the state in autocratic countries, the most vocal opponents of such regimes, the ones who crave an escape to the West, are the ones who fare the worst after emigrating to free, democratic societies such as those in the Western world. You can think of it as an inversely proportional relationship between one’s dislike for a government or a regime and their likelihood of doing well in a freer, Western country that runs on capitalist principles.
They, unlike those who make their own little worlds at home in spite of the surrounding conditions, those who make the best of the situation, these vocal dissidents have let themselves be defined by what they perceive to be the restrictions of those societies. In other worlds, their lives have become dominated by what they criticize; they themselves have become the voice of those restrictions. Their very purpose of being is now defined by those societies: they live to criticize them. Because of this, their transplantation into a Western society would be fruitless. I don’t say this triflingly; I saw this happen first-hand.
These particular people would quickly find the faults in such a society (because they have become wired to do this) and would become dissidents of the West, criticizing the overt commercialism (for example) of such a society. They would find no solace in the freedom offered there and would instead resort to vocal criticism of the faults of that society. They would make poor use of the facilities of that society, they would contribute little or nothing to its betterment, but would instead fill their days with discontented moans. They’d likely pen editorials about the shackles of the West, etc.
If you want immigration success stories, you should look for those who can find the good in any situation, those who in spite of the conditions imposed on them, managed with what they had, provided good lives for themselves and those in their families, and were bright points of light in those autocratic societies. Get those people in the West and they’ll likely do the same, if not more, with the opportunities provided to them in those free societies.