I think you're absolutely correct. The show was campy, and in time, would have become grating and fallen apart.
Star Wars, once lauded, has been milked dry. There are a few good works, but by and large they're beating a dead horse.
The same thing is happening to Marvel. People checked out after Endgame.
Game of Thrones was so near to perfection. It had an unusually large cast of a hundred characters and an expansive world to draw down. But even if the new show is good, the magic is gone.
The mystery of Stranger Things after season one ended. We're getting a rehash with common character tropes you can find anywhere.
The allure of Westworld softened after season one attempted to open up to bigger themes, but actually cut down on the possibility space.
The third Godfather. Dexter. Every single Jurassic Park but the first. Jaws. On and on.
Chiefly, it's simply a function of multiplied probabilities to continue with a success streak. Eventually the odds do not pay off in your favor.
But I think another contributing factor is that our brains begin to fit the shape of the setting, the motifs, the character arcs, the narrative world - and we just aren't surprised or pleased any longer. Few people would ask for twenty seasons of a show. Or ten movies in a given franchise. Our brains learn the shape of the landscape and grow bored.