By your theory Square should have stopped Final Fantasy a long time ago (I agree, but...). Sure they have the same faces, but Mario's been in everything from platformers to racing games, RPGs, and puzzle games. There's alot of variety, but they use the same mascots. So what? They're usually all fun to play. If they weren't they wouldn't be selling so well.
and yeah that GT game looks like it was made for the DS or GBA