Not really. Smash was always a crossover franchise, the fact they add more characters (even non-Nintendo ones) is not harmful. If Mario Kart gets some crossover with other Nintendo franchises, as long as it doesn't betray the gameplay or the cartoony style of it, there won't be trouble (and the Mercedes DLC was free and fun). People will always play the profesional-made games, even if Maker cuts their sales a bit, I'm sure that what they gain is more that wat they loose in that regard.
If you are refering to the lokes of F-Zero, Golden Sun, and other medium tier titles, they will appear when Nintendo figures out something to do with them. Fire Emblem was also a dying franchise and now it's pretty popular.
If anything, this is the age for NEW IPs from Nintendo. They breaking into the mobile market and need to appeal to new audiences will make them experiment more than ever (sometimes with Splatoon success, sometimes with S.T.E.A.M. failure).










