Well, if you grew up with a certain standard of living and you went off and did the right things and studied the right subjects and got the good jobs - only to find out you cannot achieve anything close to what your parents and grandparents have l, there is a certain part of you that’s going to be resentful and hurt and angry.
As others have said “Happiness = Reality - Expectations.”
For the Pakistani or Mexican man coming from poverty stricken, crime riddled, violent places in the world to America that’s a major step up in quality of life. Whereas I, an American, making $150k per year as a software engineer literally cannot afford a house within two counties of my mother because the costs of housing in those areas are so sky high that I would have to squeeze my wife and three children into a small 2/2 condo in a rough part of town. This would effectively revert me back to the standard of living my poor immigrant grandparents had when they came to America.
In any case I work remote and instead live in a reasonable home in a moderate income area instead so I’m just fine. But that right there is a large part of modern generational bitterness among the youth. Even those that on paper have made it often haven’t.