Now there's a strawman. All the facts on wikipedia are widely known to some group of people, but nobody knows 'em all. Though actually, you've just given me another excuse to link to my new blog in which I'm (perhaps slightly facetiously) attempting to become an expert on everything by reading every one of wikipedia's 3.5 million articles: http://projectomniscience.blogspot.com/ ... I only started it two days ago but I've already done both aardvarks and zebras.
Absurd examples like people's cats and random numbers are not really the problem and I suspect you know that.
They would be, if you removed the notability guidelines. Well, the cats would be.
It's the abusive use of the guidelines (evoked as gospel) by deletionists to keep n00bs out of their playpen.
Possibly. I've never actually tried editing wikipedia, only reading it. On the other hand, I have been through Articles for Deletion a few times and the vast majority of stuff that gets deleted clearly is crap -- vanity articles and the like.