If people don't know the movie is coming out though...
Sure, MCU nerds will go (and not even all of them will since it will for sure be a movie many want to make a statement against for whatever reason, I can already see it), but people really forget the power of the press that these actors do for movies until it's not there.
Late Night Show appearances are aimed at older demographics. Youtube appearances such as Hot Ones, doing the general stuff for GQ, Vogue, etc is aimed more at Millennials, but then there's also the avenue of a Mr. Beast crossover which is one of the biggest ways to advertise yourself right now to people of all ages all around the world. Then to appeal very specifically to Gen Z, you take all of that content, and chop it up into small pieces and throw it on TikTok.
That cycle of advertising a movie hits every demographic and makes sure that people know that your movie exists and hopefully have seen enough about it that they want to go see it if they were ever on the fence (or maybe they didn't even know it was coming out). Without that cycle, movies are already reportedly being hurt by at least 15% per movie (this is post-Barbie/Oppenheimer weekend as those were the last films to have a full campaign with actor promotion).
Now it still is August and it's a slower movie going time anyway so things could change, but i'm inclined to believe without that promotion, big budget movies are for all intents and purposes DOA unless a deal gets done. For example - The Creator looks amazing imo and is an original sci-fi picture so I want it to succeed. But does anyone know that it's coming out in just a few weeks? That film couldn't have been cheap, either.