I often use a commercial VPN service, which I suspect is not rare among Lemmy users. Most of the time, I'm able to post to lemmy.world, but on occasion I am not. The default web UI provides zero feedback, just a spinning submit button forever, but if I look in the browser dev tools, I can see it's being blocked.
I understand that some limitations are necessary to prevent spam and other abuse, however this is a very blunt instrument. The fact that I have a 10 month old account with consistent activity should outweigh any IP address reputation issues.
Perhaps the VPN limitations could be narrowed in scope to cover only account creation and posts from young accounts.
It's kind of not. It does appear to be at least theoretically possible to self-host any or all of the major components. Unlike ActivityPub projects, however, it doesn't seem like anybody is doing that and offering services to the public.