For a lot of the commonly used libraries, the doc is sufficiently decent, though sometimes unintuitive to find. For core stuff I like the hyperspec as much as the next lisper (and opening it on a symbol is just ,h for me) but there's also http://clqr.boundp.org/ that not everyone knows about, it's a great little reference to have printed out at my desk. And there's situations like how part of pretty much every Lisp, available through ASDF, is UIOP, a great little portability library. Its doc is at https://asdf.common-lisp.dev/uiop.html and it originates in the source repo from a Lisp script taking doc info from the source and applying a .texinfo template to it. Pretty bespoke. But this is also just part of the cost/benefit of CL: it's very unopinionated, unlike say Java or Clojure, and so lets individuals and teams do what they want which naturally isn't going to be the same worldwide. I like certain doc (especially at least one example of using the thing) in repo README files, others don't, nothing forces one way or the other.

Once the confidence for Lisp is there though, you're right that it's not a big deal. It's very nice to jump-to-source for everything, including SBCL internals, and modify things even. I can fix some bugs in a dependency library, right now, without having to file an issue/pull request to the library maintainer and waiting for a new release, and that modification can even live in my source tree in the interim as just a bit of code that runs after loading the main library and then redefines one of its functions or whatever.

I disagree that any effort needs to be made on attracting lone wolves, less even than trying to make editor support better for beginners; the loners will come on their own in time. Not because CL can only be used by loners (million+ lines of code projects made by teams demonstrate otherwise), but because it's a very good multiplier for that situation.