You could call okcupid feature complete. Keybase however still had plenty of exciting greenfield work to do (IMO) - my friend and I emailed them asking to pay for KBFS but the founders declined!

And thus why most software is utter crap too. When people first talked about holding software development to the same standards as professional engineering I thought it was crazy, but the longer I've been in this the more I think it is absolutely required - for this reason if nothing else. It's called work for a reason and the un-fun stuff is often as or more important than the fun stuff.

Leaving aside the fun, maintaining them is also often not economically rewarding compared to building the next new thing. I dare say the founders of these sites will be happy enough with their decision even if they are called out once or twice in comment threads by critics with no skin in the game.