A LOT of nostalgia and brand loyalty.
If the same game was released by anyone else, it wouldn't be that much praised. And I really did enjoy the previous one.
It was the first time Nintendo fans played an open world game, they acted like it was revolutionary and life changing. Besides the physics system there wasn't anything amazing about it.
The world is very dull and lifeless, there is even less enemy variety than RAC Rift Apart.