Marvel doesn't see the same success in the conventional gaming space as they used to. A lot of poor quality control from games last gen like X-Men Destiny, Spider-Man Edge of Time and basically every Spider-Man after that, Activision price gouging the fukk out of people with their old Marvel games, SEGA shytting themselves with the movie-based games, Marvel themselves being draconian with how their IPs are handled like with Capcom in MvC3. Just a bad move for them.
Disney's doing the thing inch by inch. They're obviously interested in asserting themselves back as quality publishers and the Marvel IP would do them some service.
Personally? I think Marvel vs Capcom 4 will be the 'first' real Marvel game we'll see this generation.