Quoted from rai:Because once a character dies they can’t do another movie (cough Black Widow).
After Downey's Doctor Dolittle just bombed, perhaps he's rethinking taking off that armor & losing out on those guaranteed Marvel megapayhecks. And Marvel just introduced time travel & alternate timelines to their movie universe. If Marvels grosses start slipping while shifting focus to new characters, then rest assured, he's going to put that armor back on at some point.
And when are the new IMVE rolling off the line? Really curious if the code will be updated.