Mediawiki is trivial to cache, though. For all intent and purposes most hits will be cache hits, and thus "static" content.

I'm also shocked at the tens of thousands per month, it can't possibly be hosting alone. It has to be that the maintainer had a generous salary or something.

I have no idea how it works, but given that the read:write ratio is probably 100:1 or more, certainly it could just serve static, prerendered pages straight from the filesystem or something like memcached?