How is Smash Run a campaign? Not only does the whole thing take just a few minutes, but it's a multiplayer mode. I can't fathom any comparison between it and a 15-hour single-player mode with an actual story and cutscenes.
If Smash Ultimate is not a new game then Street Fighter, Mortal Kombat, Tekken, and Soul Caliber haven't had new games in many years either. By that standard the last new Smash game was Melee.