@Superchao I feel it's because there were so many months long droughts between releases on the N64 that if a game came out and it was good, the word that 'this game is good!' would be able to spread a lot more easily than if the system was having new releases every few weeks or so.
I mean criminy after Mario Kart 64 was released in North America in February 1997, the next game didn't come out until August.