Nintendo’s Super Mario franchise isn’t really one series any more. It’s split off in a number of different directions, each catering to a slightly different group of fans.
The different subseries have enough in common that someone who just enjoys “Mario games” can get something out of all of them, but each type of modern Super Mario game is clearly designed with a particular type of player in mind. And it really benefits their overall game design.
One of the more recent additions to the formula is the Super Mario 3D series, kicked off with Super Mario 3D Land on the 3DS and continued with Super Mario 3D World on the Wii U.