Coz just about everyone wants to be that one guy in Nebraska thanklessly maintaining this bit of digital infrastructure, apparently?

Yeah me neither.

I think the only thing that would convince people to move away from curl at this point would be if curl had a heartbleed level vulnerability and failed to fix it quickly.

Curl is so important that if it had a heartbleed and didn’t patch, someone would and people’d just apply it until it was fixed in tree.

Individuals don't but lots of companies do, so that they can threaten to rugpull it later if you don't pay them millions.