Re: For how long will the MCU go?
There's absolutely no reason that Marvel Studios would try to commit suicide by "rebooting" their gold mine.
Yes, someday people will get tired of the superhero subgenre, just as they got tired of any other subgenre you can think of. Once that happens, a reboot would be meaningless, and seen as a cheap act of desperation. Instead, when that sad day comes, Marvel Studios will likely just quietly close up shop and be happy with a long and successful run.
I estimate that day will happen 53 years from now.
THE COTTON AVENGERS
...They move like slick cotton on oil.