Earlier quoted context omitted.
I agree people seem to be either "the free market solves all problems" or "capitalism is slavery and must be destroyed" (but don't focus on an actual viable alternative). I'm chipping away on my own alternative which is a bit of a hybrid. Competition and inequality between individuals but not between groups within society. https://opensocialism.com/tldr-for-software-people is a good intro for IT people.
Ignoring human envy and jealousy, what is wrong with inequality between groups?
A bit cheeky, I know, but I don't think you can just write off emotional results of systems.
But to answer in better faith: I think [Rawls's Veil of Ignorance thought experiment](https://en.wikipedia.org/wiki/Veil_of_ignorance) is a good response here. In short (skipping how he arrives at the conclusion): when judging the quality of life a system produces, measuring by maximums (or even averages) is probably not the way to go. Median and mode are also very important dimensions to pay attention to.
Also worth noting: if we did live in some future utopia where "inequality" really meant the difference between "all my needs are easily met with little stress" and "I experience nearly constant bliss"... yea, we can have some inequality. But, pockets of the developed world aside, we're not there yet. Not even close. So long as we have around 50% of the world in poverty, and more than 1 billion children in extreme poverty, aiming to "lift all boats" faster than the amount a "rising tide" does is a discussion worth having.