It's not that people aren't attempting to better themselves, it's that this is very much a feature of American capitalism, not a bug. Minimum wage is less than half of what it should be in 2020 when accounting for inflation and increased productivity, and corporations continuously lobby to keep it that way, passing the rest of the burden onto the government. A recent study found that
minimum wage workers cannot afford rent in any state. Minimum wage would have to be increased to $15/hour in most states and $20/hour in certain others in order to remedy the excess burden on welfare and taxpayers.
And then of course there's also privatized prisons and the 13th amendment continuing the never-ending cycle of slave labor, poverty, and recidivism. The result of all this being that wealth inequality in the US is currently worse than it was in France circa 1790. You probably already know what major event happened during that time period, so I won't bore you with a history lesson.