Nozick's thought experiment isn't about modern capitalism, which can be and should be trivially condemned without the work of gedankenexperimenten.

It's about how a utopian society could and/or should respond to changes in resource distribution, and how entirely consensual behavior and exchanges between people can still lead to situations that are problematic.

I think Nick's utopian egalitarian society would arrange for the amazing basketball player to have the job of playing amazing basketball, but the same income as everyone else. In exchange for playing basketball really well, he doesn't have to, say, clean toilets.

Making everyone have the same income means there is already a big infrastructure to manage how resources are allocated in this society - it already can't have been a free-trade system with currency that can be arbitrarily sent and received.