It started out that way, but these days we have several other developers who are pretty active. You can see from our stats on ohloh: https://www.ohloh.net/p/musl/contributors?query=&sort=commit...

Also, without the work of the entire community testing and reporting issues getting various packages to work with musl, it would have taken forever to get this far. Testers and bug reporters are seriously under-appreciated!