There in a really tight spot with MOS, obviously the hulk wasn't a box office smash hit so a reboot isn't going to guarantee the money they were hoping for. Obviously SR didn't perform as well as they wanted and I think the question going forward is, can a sequel make its budget back with half of the fans disliking the film. Its a risk either way, unless they were to do a reboot/ prequel to SR, keep the same characters but do the origin, I doubt that will ever happen though. Or they could invest that money in another property like Green Latern. After Iron man I think they would rather invest their money in a lesser known character than a movie like speedracer.