@pj @kline @wolf480pl @nytpu Well Perl is probably not the greatest example, although it's virtually available everywhere, and when you have people writing in the bash dialect on a regular basis and you know how much of a pain bash is to bootstrap (and how unspecified it is so no alternative implementation or even actual linters…), nah Perl is fine.

I do think a shell replacement should be more comparable to like lua in terms of bootstrap, but in no way does it needs to be present everywhere, it just needs to build on a POSIX system, then it's effectively a dependency.
After all people use buildsystems other than make(1) fine, so a different shell is entirely possible.