yeah they were, and they took the mcu jobs because they pay more than oscar bait or comedy jobs.
The MCU is probably the only film franchise where the head producer let's the talent breathe and make different genres of film because he's a film nerd himself. That's not to glorify Kevin Feige, but he's probably the only producer in modern history who's learned how to let talent make the stuff they want within reason and the money just follows the film, as opposed to the opposite and shit just crashes and burns (looking at you DC..)
There is a REASON the franchise was elevated after 2016, and films have been more consistently rated positive for its writing/acting over just spectacle. This is why you basically only hear about positive experiences working for Marvel after talent leaves.
Like fucking Scarlet Johansson sued Disney for lack of a payout on Black Widow after co-producing the film, and after being paid, STILL decided to work and produce with Feige because of their friendship. Sure, money is the motivation, but you can very clearly see that the culture at Marvel is just 100x better than other Hollywood studios.