I'm not going to argue that the Transformers movies were examples of good narrative or good characters, just that the characters are at the center of that whole brand. Optimus Prime, et al. There is a narrative that defines good guys and bad guys and sets the stage.They really don't. Have you seen Michael Bay's movies?
They have a lot of explosions; I'll give them that. Strong narrative and developed characters? Not a chance!
WotC has narrative and characters up the wazoo.
Hollywood bought the movie rights because of the characters, and the nostalgia attached to them.
There are lots of D&D characters from 40 years of games and books, but do any of them work for building the brand?