Board Thread:General Discussion/@comment-24822639-20140623101206/@comment-5185663-20150715181747

Thing is, you don't have to worry about actors not being immortal because Kevin Fiege confirmed that they'd just recast without rebooting (like Bruce Banner for example) People also say that superheroes will die like westerns, but I think that is not the case considering that superheroes are of unique genres and the novelty of them all living in the same universe is an extra big help to any and all future films because there is less risk when people want to see this fully-realized fictional world expand. Not to mention, Marvel Studios doesn't work on any big-budget projects that aren't superhero films/in the MCU, so they'd never get sick of it and move on.

tldr; I think the day the MCU dies is the day Marvel goes bankrupt.