I don't know about Alpine specifically, but many distributions put a lot of red tape around becoming a maintainer (for good reasons). I just don't want to get into it. AUR from Arch Linux has an interesting take on this — anyone can become a maintainer in a matter of minutes — and while that results in some low-quality packages and the expectation that you're supposed to review everything you install (which is easy though thanks to the excellent package format, which Alpine also uses with minor modifications), most of them are fine, and AUR gets a lot more maintainers than any other distribution.

You also don't put any obligations on yourself by becoming a maintainer on AUR — you can always orphan a package in less than a minute, no questions asked. Some users actually place new packages on AUR and orphan them right away. If it's of any use, it usually get a volunteer maintainer within a few days.