Maybe my systems aren't exotic enough to experience the uncommon breakages.

The majority of issues are caused by Python applications, because Python packaging in Nix is still very rough. This isn't Nix's fault though, its the fact that pip sucks and most Python software uses a simple requirements.txt. Hopefully one day Poetry and UV build helpers will be in Nixpkgs.

You have to be active in the community to get your work merged in any decent timeframe. I think this is the most annoying part about the Nix ecosystem.

Definitely agree. It can be hard to get things merged or even reviewed. The simplest option to improve this would be to give more people write access, but of course lowering requirements for getting it would be a risk for security and stability. Nixpkgs automation is frequently improving, which will definitely help.