Re: What would have happened if Avengers failed?
The failure of the Avengers movie would have had an impact on most major studios:
Disney/Marvel - The blame for the disappointing box office would have fallen directly upon the alien protagonists. The beautiful, mythological aliens from Thor would have been spared, but the Chituari, the Other and Thanos, along with the Battle of New York would be ignored in future MCU films. The company would have looked to its street level heroes, with a series of Marvel Knights films taking the place of more expensive alien based films such as GOTG and the rumored Inhumans film.
FOX - With no need to keep up with the Joneses, the less costly XMFC 2 replaces DOFP on the FOX production schedule.
Sony - With the softened demand in superhero films, the studio takes a less aggressive stance with it's ASM series. Two sequels are planned (rather than three) with the films being released every three years (as opposed to every two).
Warner/DC - Warner is pleased with its box office take from MOS, and schedules a sequel for 2016. Batman continues his post TDKR retirement, and a future Justice League film goes from "maybe, someday" to "never going to happen".