I think, given that SO has become an encylopedia, it needs editors in addition to moderators. My one contribution to stack overflow was a comment on a question about a strange TLS problem, where I explained what was happening, and mentioned it was worked around in the latest OpenSSL and linked to the diff where my workaround had been accepted. Then a few weeks or so later I got a message that I needed to fix my comment because something. I was motivated to fix the problem in openssl, and to respond back to help any other people who run into this, but I'm not motivated enough to fix my comment to follow community rules.
There are editors. Any user with something like 2000 rep can edit any question or answer. I do it all the time. There's even a queue of questions that have been flagged in need of editing.
