Well there were three separate major studio live-action multi-film Spider-Man movie franchises in under 20 years.
I'm not sure what that proves, I just still find it surprising.
I suppose if nothing else it proves that Spiderman is an IP that's always had a very large following in the comic-book nerd world. iirc, when I was a kid/teen, Spiderman was always among the highest selling comics. Just an extremely popular character, so maybe that's why they can get away it?
Something that is materially different compared to Harry Potter, though, is that Marvel comics had several different Spiderman comic series. Like, 4, I think, or something like that. Amazing Spiderman, Web of Spiderman....some others. While basically the same character, there were some differences, and the stories/history was different within those series. I believe Toby McGuire's franchise was based on one comic series while Andrew Garfield's was based on another, thus why, for example, Toby McGuire's character natively shot webs from his body while Garfield's character shot webs from mechanical contraptions he built (I think that's right....it's been years since I've seen any of those). That follows the different Spiderman versions their movies were based on.
With Harry Potter, you don't really have that. There's just the one book series. BUT, since the first movie was 25 years ago, and the last movie was 15 years ago.....it's just my old age creeping in, making me think "But they just did that!" I guess the new generation of kids are primed and ready for their own version.
The only thing I can tell you for sure is that LOTR
will get remade at some point, and I'm going to hate it. Peter Jackson trilogy 4 lyfe.