I think it's just the franchise being pushed as the be all end all in otaku culture for most of the 2010's and just getting endless fucking stuff of dubious quality every couple weeks, all treated like it's supposed to be the be all end all. It's also like the Fate fanbase just settles for literally anything the franchise does and automatically parrots how it's all equally brilliant just for having the label Fate.
As a result it's all just become one big otaku meme now that's left it without any real distinct quality or direction as a franchise to it when it can just do literally whatever with it's extended universe provided Sony Music Japan and ufoTABLE are there to carry it with marketing and flashy visuals. That just kind of feels like how Japanese pop culture works in general now judging by Demon Slayer.
I don't even think Type Moon particularly has any control over it's own franchises anymore either and might as well just be another division under Sony Music Japan's Aniplex label since the only time anything ever seems to happen with the company anymore is when Sony says it's okay and it's hard not to notice.