Thanks, Jason, that is helpful!
I highly doubt that. The biggest box office was Black Panther (or Avengers I, adjusted for inflation) at ~$700M (domestic) and the 11th highest of the 21 (Iron Man 2) was about half that, adjusted, and the bottom third made less than a third of that (
source). So I don't see how you get to a "majority of the movie-going public" for "most" of the movies.
Or, to put it another way, the avg ticket price in 2018 was $9.11, so about 77M tickets were sold for Black Panther. That's a lot, but 263M people saw at least one movie in 2018 (
source), so even if you assume none of the 77M Black Panther tickets were repeats (obviously not the case), it's still only 29% of the people who went to the movies that year, for the biggest Marvel movie. It also doesn't change much if you eliminate only "infrequent" moviegoers.