For example, while 1.21 was the latest version announced, the current is 1.22.2. Is the site just left to run out of principle and convenience for people to have an easier place to download it, or is it something else?
For every piece of an open source project, someone has to do the thing. In the case of updating version numbers on websites and writing PR pieces, etc., we don’t have anyone who does specifically that, and the people who take time from other things to work on those things don’t prioritize them as highly as other things they’re working on.
So, those things get updated when someone gets around to it.