I don't disagree that it's one of the best known franchises and characters in gaming history, but a reality show?
I don't think "reality show" is the best label for it. It sounds like it's simply a game show, but these days the label "reality show" has subsumed game shows in people's minds.
As you point out, the concept itself has already been successful without the Pac-Man branding, so the branding just seems pointless in this case.
It's not pointless, because producing TV shows costs money. What better way to get the funds to make a show than if the whole show is one big commercial for somebody's product?
There have been TV game shows based on other kinds of game before, such as
Concentration, Pictionary, Trivial Pursuit, Yahtzee, Scattergories, Mad Libs, and
Scrabble. The Hasbro-owned cable channel The Hub has
Family Game Night, which includes game-show-ized versions of a number of Hasbro board games. Heck, there are two game shows based on tic-tac-toe,
Hollywood Squares and
Tic-Tac-Dough.