Since they're introducing comic continuity into the movies, I can understand why they would go that route. Can Iron Man really sustain itself in the movies like Bond can, though? No superhero has. Heck, no other character in the history of film has.
Then again, Avengers was a game changer. It's a major turning point in the genre. No longer are just the A-listers or high B-listers allowed. Ant-Man and freaking Guardians of the Galaxy are happening. People will go see them, and then they'll probably see Ant-Man and Wasp (I'm assuming she'll be in the Ant-Man movie) in Avengers 2. We'll be seeing Black Panther and Doctor Strange and Namor soon enough probably. Not to mention all of the sequels that will build out of those.
The first Iron Man was often called "realistic." Then we had Iron Man fight aliens alongside a thunder god, and a giant green rage monster. The sky is the limit now for what is acceptable in a superhero film. We need no longer have any hero constrained by realism are free to get into some of the really crazy stuff. We've got Thanos coming. Freaking Thanos! An intergalactic warlord who kills people to impress Death. Maybe, just maybe the Marvel Cinematic Universe could have the staying power of the Bond franchise. People still love superheroes, so they're not going anywhere any time soon.