I think Niantic is struggling because they go the franchise route. They have few new ideas for their games, it's just mostly a new skin. But i haven't really tried the Harry Potter game and Pikmin Bloom so maybe i am wrong.
The Harry Potter game was a little bit more complicated, I think PoGo was probably the simplest, at least at launch, I'm not sure what its like now, and other than being a super well-known IP is partially why it was successful IMO. I guess you could probably point to that also being one reason why the HP game wasn't as successful despite also being a popular IP. I haven't tried Pikmin Bloom.
