There is no need for a retcon; the series has just started. If anything, they shave back the scope of the films and the budgets: investing three hundred million dollars into a film is a dangerous gamble. They think smaller and try to work an arrangement with the studios they've granted the license for to avoid over-saturation. If anything, they should alternate the releases: one MCU film a summer and one from Fox or Sony. It will keep it fresh and prevent the blockbuster fatigue that some on the board has described.
Will they do it? No. The studios are in a mindset and cannot be talked out of it. As long as the quality is retained, Marvel Studios has nothing to worry about. Marvel Studios has thus far not made an incorrect step. The same cannot be said for Sony...S3 was bad, and ASM bunted the ball, but did not secure a home run. Fox, meanwhile has gotten its act together and has been good with FC and TW, atoning for the atrocious preceding releases (X3 and FC.)