The reason wikipedia is so great is because it is malleable, if it had to be 100% accurate, it would cost 100 times more to maintain the content that they do. You sacrifice 1 or 2 percent of accuracy for the product being offered for free, which is well worth it.
If you open up an old encyclopedia, it's full of errors and falsities because the world changes. The world changes faster than anything can accurately update the database of information. Their current system seems to be the best method so far because errors are eventually corrected and it offers a wider variety of content than those old encyclopedias used to.