It's easy to see why this happens. After all, the one person in the world least qualified to identify the correct answer to a given question is the one who asked it.
That depends on the context though. If the person is asking a question because something isn't working, and an answer solves the problem, they are then the best person to qualify whether the answer was correct.
Though yes, if you are asking a question from a more academic perspective, then you wouldn't expect the person asking to be the best judge of the right answer.
Other times, the best answer is something along the lines of "You're approaching the problem wrong.", such as in "I'm storing customer IDs as a comma separated list in a column. How do I join that to the Customer table?"
Too many people will offer up horribly complicated solutions that technically do what the questioner asked, but the real correct answer is "Normalize your schema."
So to point out the obvious with these q/a sites, caveat emptor. One has to look at the context of the site and the question(s) asked to determine what is "right" or "wrong" and what assumptions are made, for right or wrong.
1 - The fast, but "good enough" answer wins out for the short term 10+ votes (and "Accepted status), then the question falls into the mire, occasionally floating to the surface via a Google search, where I might get one or two votes.
2 - My answer is accepted, enough that noone else bothers to partake in the question, and it falls off the radar having received maybe 1 or 2 votes.
In terms of getting good answers into the system, I guess things are working as intended. In terms of creating an engaging experience for the questioner and answerer, this seems sub-optimal.
Unless the question is on a topic I love, that makes it into work. Is the point of SO to gain points to look clever in front of your peers or to actually help people? I'd rather just write a post blog to send someone to, since it stops other people editing it and I'd get all the credit and the traffic.
Perhaps I'll give it another try - maybe it's settled down a lot since launch when pretty much every question was getting a quick fire answer in minutes.
One solution is to ask questions - you can get reputation for that as well. Once you have reputation, you can down vote stuff.
Another is to look for difficult questions that haven't been answered. You can even get a badge for answering a question that's been open for more than 60 days (or something along those lines).
It's "question & answer" versus "learning." SO is the former. But answers alone do not equate to solid learning. Everyone can read Wikipedia articles on medicine all day, but it can't compete with the wisdom a professor or doctor can give you.
The scoring doesn't help. Usenet was pretty cool in the day because anyone could submit an answer and bad answers would be questioned by people with experience (many forums are still like this, and Hacker News is very much like this despite the points). On Stack Overflow, even if you have enough points to comment, it seems like hardly anyone bothers and there's little "calling out" of sloppy answers.
I haven't regretted trying it though. It's a well designed site and there are some great Q&As. I suspect in certain disciplines it's very useful. But, for me, I've realized working on my books and other documentation will be time better spent than having to play a game for points answering questions against the clock on a social network when I'd rather just help and teach folks instead. So, I tried..!