I don't know why anyone is bothering to compare anything else to Endgame. It's a freak of nature that has two things going for it. 1) The culmination of both a 10-year movie series AND specifically the conclusion of a very big and popular movie last year.
and
2) The apex of response to our "spoiler culture". The fact that social media has reached so far, and that a vast majority does not want to live without it, but also does not want it to ruin their moviegoing experience. The response is the "need" to see the movie as soon as it comes out to prevent strangers from "ruining" it for them on-line or even in real life. I ran into some friends with their kids at the theater yesterday and they were talking about they felt like they had to go this weekend or else other kids would have spoiled it at school.
As another comment - around someone's mention of "Marvel doesn't give me what Disney used to". Sitting in that theater with my 15 year old daughter - I realized that THIS is her "Return of the Jedi" or "Jurassic Park" or whatever movie you want to compare it to from your youth. A movie that just simply left her agape from the sheer entertainment.
This is no spoilers here - but the way that Marvel set up these characters that you care about across multiple movies and was able to put it all together into a story where there were half a dozen characters that really got completed arcs was really wonderful.
I don't mind at all for Marvel to come into the parks. I am also approaching 50 and I was not a big comic geek as a kid (was a movie geek) but I can appreciate how "right" Marvel is getting it, and if this leads to the future of my entertainment in the theme parks, then so be it. I am not sure how long Marvel can keep up this wonderful story-telling (I give all the credit in the world to Kevin Feige for this) but I really am looking forward to where they go from here.
Edit: And to the argument for IP free attractions - I am afraid that we will not see that very often anymore - but it doesn't mean it can't work. And I also often argued that many of those original attractions that we don't associate with IP were in fact part of the "Disney brand" IP. Adventureland was based on several Disney Movies and "True Life Adventures", Frontierland on the
Disneyland stories of Davy Crockett and many others. Just because we've forgotten the IP doesn't mean that it wasn't originally there.