Are crowds really all that wise?

You might try actually reading Surowiecki's "Wisdom of Crowds". Once you get past all the hype and glosses on the book, and the book's introduction, you will find that the "wisdom" of crowds is restricted and only functions under particular conditions that rarely hold in the real world. But when they do hold "crowds" actually do function well.

Wikipedia does not satisfy those conditions. It seems to be mostly accurate for non-controversial technical information, but I wouldn't trust it much on anything.

Probably not. Herd behaviour is not necessarily wise, mostly to the contrary. Buffett wasn't successful because he followed the crowd but the opposite.The "madness of crowds" is well documented. Wisdom of crowds? No thanks.