> If both aren’t done by many humans, what’s left? Sports training and massage therapy? Sports training might not even be safe…

Peacock tails.

As in, things where the effort itself is the point, to show off that you are capable of surviving when you consume resources so extravagantly on something other than (or even detrimental to) mere survival.

This includes stuff like hand-made art, being in a literal cult, extreme sports, and also refusing modern medical interventions/seeking out infections.

You may ask how someone can get paid for those things; I don't know, but we did manage to monetise talking to each other (ads on Facebook) and being locked in a house with some strangers while everyone's under surveillance cameras for a few weeks (TV show Big Brother).