The American dream has always been a fiction for huge segments of the population.
What we're talking about, technically, is the idea of meritocracy. If you work hard and smart, you should thrive. If you are dumb and lazy, you should flounder.
But that is not at all the case in the United States.
We have smart people working 2 or 3 jobs only to barely stay afloat, and we have morons sitting on mountains of money.
Briefly in our history we had a strong middle class. The Greatest Generation built it, wrestling wealth away from the top 1% with strong unions. Then they handed it over to the Boomers, who pissed it all away, and destroyed the power of organized labor.
Boomers inherited a nice system, but refused to fight to expand it. The 5-day work week, for example, was supposed to be just a stepping stone. The people who originally fought to get it would have never believed we hadn't gotten that number any lower 80 years later.
Boomers allowed the minimum wage to stagnate. They allowed pensions to go extinct. They voted time and again against universal healthcare. They did nothing to stop predatory lending. They did nothing to stop the explosion of tuition prices. They did nothing to make social security viable for future generations.
The stupidity, gullibility, self-entitlement, laziness, greed, hypocrisy, and frankly psychopathic governance of the Boomers has essentially wiped out all the progress that came before them.
They are retaining a death grip on their power, and have used it to give us a choice between a Trump cult, and Democratic party that is virtually indistinguishable from 1980s Republicans.
Oh, and when they found out that they were killing the planet, they just stepped on the gas and killed it faster.
So, yeah, the American Dream, if it ever really existed, is absolutely dead right now.
When the boomers are all gone, the voting power of millennials and gen z might have been able to fix things ... But honestly, we're riding the razor's edge with fascism right now, so it's a coin flip whether or not we'll even have a democracy with which to repair things.