I dont know the actual history of shrines, and I dont remember it being called shrines either back in the early 00s. Maybe it was called shrines by the actual "community" but I didn't see that word around at least as a simple viewer of homepages.
But I guess it could have been called shrines or similar, and anecdotally what I thought/assumed/figured was the idea, was that you'd make a "shrine" for something either as an individual page, or you'd have one or more shrine-pages on your homepage.
And they were often sort of, works of art that you finished and left to be viewed as it was. So if it was a shrine to just like a tv series that ended, or a deceased pet, or like a boat or car or just something that you owned and loved etc. You'd make the shrine to your liking and then leave it as is. Obviously someone would re-do it from time to time, but afaik it wasn't supposed to be actively updated or worked on after being uploaded. Obviously there wasn't a rule against that, but at least that's what I picked up from just spotting these in the wild both back then and during the web revival era. It's a sort of place of rest/place of memory/place of thought/love etc so it kinda makes sense in my head at least that it was to be a finished piece of art, rather than how they'd update and work on other aspects of their website.
Idk if that many any sense. It was honestly rare that I came across "shrines" back then, but the ones I did, that was the vibe I was getting at least.