Granted that Marvel hasn't shown a good head in creating games in the later years...
We all know Marvel's policies banned the much-requested and fan favorite X-Men characters from appearing into the game.
Also, is very likely the license to create a new Marvel game was very expensive.
What if Capcom spent a whole lot of money in getting the license and then they were left with a very limited budget for the game development (which would explain the low quality graphics and recycling of MvC3 assets), because of Marvel's greed? Worst thing, the game lost appeal because of the veto of characters... and so it seems hard for them to recover from the financial losses of the game.