oh sorry i didn't read carefully, i thought it was 3 new games period.
And why wouldn't they? Mario is only the most recognizable figure in the industry and I'm sure after the success that the first one they probably put a big chunk of change into the sequel.
I doubt it'd be a pure sequel - but I could easily see Ubisoft putting that team on a bigger IP after the success of the first game. If they continue the partnership with Nintendo, maybe that's adding the budget to make even a small franchise into a AAA release.