The Super Mario Bros set is legendary and has been around since the 80’s.  Super Mario Bros became popular as a 2D platformer for the NES and has evolved into one of the biggest video games series of all time.  Ever since the Super Mario series went back in the mid 90’s for the N64 it seems like the games have only managed to get better throughout the 00’s and the 10’s.  

With the recent success of games like Super Mario Odyssey there really seems to be no reason why Nintendo should go back and start making 2D titles for Mario.  However, if Nintendo decides that they want to develop 2D titles for consoles such as the Nintendo 2DS or the 3DS for an example that would be perfectly understandable.