I think that there are a lot of people out there who don't know why Marvel sold off film rights, or have some confusion as to why they did so. If Marvel had not made those sales, it is very likely that there wouldn't even be a Marvel Comics today---and that this conversation wouldn't even be taking place. You make another great point about integrating the FF into the MCU. As much as I would like to see that happen, they wouldn't be able to integrate them into the overall landscape overnight. With Spider-Man it was easy: He's only one character and a VERY young character that they'll have a lot time to develop. As much as I would like to see the FF and all associated allies and villains enter the MCU, at this point they would not have the same impact as "Marvel's First Family" like they did back in 1961.