I've never seen stackoverflow as a race to get the most rep possible. Reputation is just a "bonus", not a prerequisite to participate in the website. I like stackoverflow the way it is
It's quite likely that a user Googling for their particular issue might find an incomplete or out-of-date answer on Stack Overflow. When they finally solve it they are unable to improve the existing entry, which is unfortunate as for many "long tail" problems they are best placed to contribute.
Firstly it's accepted by the questioner - who by definition knows the least about the subject, otherwise they wouldn't be asking!
Even if it is correct and well written - then it stays accepted years later when it's no longer the best way to do something.