That’s true enough, but at that time whites were 90% of the US population, so there was arguably enough wealth then, definitely enough wealth these days, to extend entry-level jobs to the remaining 10%. When 40% or more of your population is descended from post-1965 immigrants, the competition for good jobs goes up a lot in most industries, unless enough economic growth makes up for it - and even with growth, housing scarcity is almost always an issue.