I don't think attributing what's wrong with reddit to "the same techno-libertarian idealism that informed many of the Internet's oldest and most influential communities, from Usenet and 4chan to the early World Wide Web itself." Usenet's decline had very little to do with Usenet itself, and the few groups that are still active are better than they were when Eternal September was at its height. I was never a 4chan user, but from what I hear other than /b/'s obsession with reliving its glory days it remains 4chan. I started using reddit 6-7 years ago, whenever comp.lang.lisp got its parens in a bunch over the Python rewrite, and it's a completely different community now. Reddit doesn't try to do anything about it, but being hands-off isn't the cause.