Pac-Man does a lot more than eating pellets in mazes. That's just the original arcade game he is known for.
There have been direct sequels where Pac-Man received additional abilities (e.g. jumping in Pac-Mania), as well as the franchise taking entirely different directions. There are Pac-Man puzzle games (Pac-Attack), Pac-Man 2D platformers (Pac-Land), Pac-Man 3D platformers (Pac-Man World), Pac-Man adventure games (Pac-Man 2), Pac-Man Mario Party clones (Pac-Man Fever), Pac-Man Pinball (Mr. & Mrs. Pac-Man) and even Pac-Man quiz games:
Granted, Pac-Man's Smash incarnation uses very little from the games that aren't the original arcade Pac-Man, but I think that's partially Namco's involvement in the development process, who likely would prefer the various Namco arcade classics getting represented over Professor Pac-Man or Baby Pac-Man.