The world wide web is filled with crap. That is why we have search. Search is the solution, not deletionism. Indeed, your tacit assumption is that deletion imp

The world wide web is filled with crap. That is why we have search. Search is the solution, not deletionism. Indeed, your tacit assumption is that deletion improves quality, on average. But (a) you don't consider the many false negatives and (b) you don't consider the effect of deterring knowledgeable contributors, without whom quality will decline. We know many knowledgeable people have been discouraged because of the hostility of Wikipedia editors towards newcomers. You've seen the stats on how Wikipedia edits are topping out, how a tiny core of editors rules the site. It is not hard to have a good search algorithm determine which pages are crap and which aren't. Some obvious features: the number of editors, Flesch-Kincaid level, number of edits, size of the page, number of references, etc. Automatic search will always outperform manual deletion at scale, especially for an audience as diverse as Wikipedia's.