Re:

TLDR: Nearly everyone who wants micropub support writes their own library, endpoint, or whole cms or blog engine.

I believe part of this is because Micropub requires intimate knowledge of how your own site is set up, so unfortunately can't be written as a generic solution, because most folks won't have things set up the same way, even on ie WordPress using common IndieWeb plugins

It's still a good point that maybe we need to look at creating an out-of-the-box Micropub endpoint for some of the common tech stacks.