Compare US quality of life 100 years ago to today, it destroys this nostalgic notion of Social Darwinism, which I don't think is a thing anyway.
[theatlantic.com]

The birthrates/survival to adulthood rates disprove this hypothesis on the face of it.

Idiotic. Natural selection is not about the top 1%, it's about the survivors. The only thing natural selection "cares" about is that organisms live long enough to reproduce. The only "losers" are the ones that don't live AT ALL.

In other words natural selection is not remotely about quality of life, only mere survival. Life can be short and nasty, so long as it reproduces.

So wealth inequality and other knock-on effects of unbridled capitalism have nothing to do with "survival of the fittest" or even with anything Darwin actually said.

What wealth inequality DOES have to do with is the arrogant impertinence of people who are merely lucky, thinking that they are also DESERVING and that Those Others are undeserving.

I say "merely lucky" because even if they "earned" their wealth / success / fame / whatever through hard work and skill, they still had to have the luck to have been born into a sufficiently fortuitous socio-economic milieu, to sufficiently nurturing parents, with sufficient physical and mental health, with sufficient natural talents, to be able to DO that work and DEVELOP that skill.

Weak! Charles Darwin is frequently saddled with Herbert Spencer's phrase, 'survival of the fittest.' What this article highlights, without directly mentioning such, is not so much a dependence on 'social Darwinism' or an acceptance of the 'survival of the fittest,' but rather an extreme laissez faire attitude along with a devotion to a 'so-called' meritocracy. The problem with this meritocracy is that it's without merit! It assumes that the most wealthy are, in fact, the most deserving, rather than the most deserving should be the most rewarded.