I'm not sure you can back up this assertion with evidence. Total employment is at an all-time high, yes. But "good jobs"? If you look at total employment in 2019 vs total employment in (pick a non-recession point in the past 50 years), what percentage of those jobs are full-time vs. part-time? What percentage of those jobs pay something approaching a median household income? What percentage of those jobs come with something like comprehensive benefits?
You have argued that our system does, and should, provide opportunities for all - "equal opportunity, not equal outcomes." Leaving aside discussions about whether we have anything approaching a level playing field (that's for another day, another argument!), and granting for the moment that there is at least some opportunity for any individual to succeed... that does not mean that everybody can succeed, that everybody can achieve, for instance, a median household income.
The Nationals won the World Series. The Astros... did not. That system allows for only one winner. So it is with our "opportunity" economy. For every "winner," there are "losers." You argue that we don't have, and don't want, an economy with "equal outcomes" - and I agree with that.
But... (there's always a but)... Given that there are going to be winners and losers... How much losing are we willing to tolerate? How much poverty? How much premature death? At one extreme, if we simply abandon the social safety net, we'll have lots of both. At the other extreme, we have everybody in exactly the same boat, and we'll have lots of free riders. I suspect you agree about that.
But how much inequality of outcomes do we want? How much can we sustain? This is a moral question - a philosophical question - but it's also very much a practical issue. If we allow so much inequality that we have millions of people in poverty, living among a few "winners" who command most of society's resources, we risk finding ourselves in a situation where a lot of desperate people will conclude that they have little to lose. When their choice is to watch their kids starve, or to kill some wealthy person to get the money they need, what do you think they'll choose to do? Yes, we can use legal, moral, or religious arguments to convince those in poverty that they should behave themselves... but at some point, their survival instinct will overrule those things. I don't think we want to go there.
If you agree with the above... then we're really only arguing about the details of the social contract; about how much economic inequality we're going to allow, before we correct with taxation; about what kind of social services we're going to assume a societal obligation to assure access to (one way or another) - housing? Food? Clean water? Health care? Note that "access" to these things implies that those in poverty can actually obtain them - not that they exist in the marketplace, and the poor would have "access" if they had more money.
And also, note that my argument that we have a societal obligation to the poor isn't purely idealistic. History says that oppressed, exploited populations revolt, with really nasty consequences. So there's an element of self-interest here - what I would (modestly! ) characterize as "enlightened self-interest" - which is really only self-interest that has thought about the long-term effects of unbridled self-interest.