Black Widow is getting the Disney+ premiere release at the same time as the theatrical release, which will certainly hurt the theatrical numbers. As they don't release Disney+ data, at most we'll be able to guess how popular it is, though if it does make a relative flop I bet piracy will be blamed. I wouldn't be surprised if a lot of people went to see Black Widow just to feel normal again after covid, but then again I think a lot of people are happy to leave the theatrical experience behind.
Don't get me wrong. I enjoyed the Marvel movies, for the most part anyways, but there's a lot of Marvel content I'm paying for on Disney+ that I'm not even watching. I think the new entries in the series will be the most telling. The eternals or whatever that is. If those fail to bring in audiences then we'll know that Marvel is in decline, and if Disney starts doing the simultaneous streaming releases for those, you'll know they're starting to lose confidence as well. IF Marvel is going to maintain its level of popularity, it's going to need a lot of younger viewers to make up for those of us aging out of it.
I think in Captain Marvel, when they reveal that Nick Fury's eye was taken out by a cat, I said to myself "If they're not taking this seriously anymore, then I'm not going to either."