[tlb]

The advantage of deletionism is that users can have some confidence that anything they find on Wikipedia has received some attention from editors. Without deletion there'd be an unlimited number of pages, (100-𝜀)% being crap.

If you search and don't find it on Wikipedia, you can look elsewhere. That's a better experience than finding unmaintained crap.

[skgoa]

But with deletionism an unknown (yet significant) number of pages are still crap. One of the sad aspects of wikipedia is that their idea of "maintenance" enshrines crap and their idea of "sources" makes it incredibly difficult for experts in a (sub)field to improve an deficient article. That's orthogonal to the number of pages, though.