Ask HN: Would an expert-only version of StackOverflow be a good idea?

Every time I want to contribute to StackOverflow, I get put off by and demotivated by the jarringly bad quality of the majority of new questions; see e.g. the list of new questions tagged with [php] [1]. Now this has been discussed broadly, and somehow everyone seems to have their own opinion about SO's problems.

I recently read a short rant [2] about it on Meta, and now I wonder:

Could an expert-only, high quality SO alternative work? Restricted access is hard to enforce, but some basic RegEx captcha and adjusted rules and moderation might help a lot. Would you use it?

[1] https://stackoverflow.com/questions/tagged/php [2] https://meta.stackoverflow.com/a/371375