Is that a serious question? Avengers is literally a movie aimed at children. Yes, plenty of adults watch it too, but its not an "adult" movie. Tons of adults went and watched the incredibles 2. That doesn't mean it isn't a kids movie.
More people watched the super bowl live than people watched infinity wars over the entire opening weekend.
Go to any place of business that has actual successful people(not some guys working at a fast food joint or a video game store) and ask around if they think comic book movies or football is more childish. Not one person in my entire office has been talking about Avengers, but when the superbowl comes up. Everyone is talking about it.