I wonder if ads (not 20+ minutes straight of ads!) would be less annoying if they were diverse and even moderately entertaining.

E.g., have a customer standing in front of the concession stand saying "Man, the popcorn costs an arm and a leg." followed by an alien with many arms and legs saying "Here, I'll pay." detaching an arm and a leg. The original speaker leaves with his popcorn and the alien buys itself some popcorn (another arm and leg taken off), takes a taste and says "Mmmm. Worth it!" (That might not be a great ad, but I am not that clever at advertising. However, I think that would at least make me smile if not laugh, and a professional should be able to find better concepts and execute them well.)

Having modestly different versions (like openings for The Simpsons) could be a cost effective way to made different versions that could actually draw attention by trying to see what is different and to see Easter eggs for movies for frequent theater goers (or those staying for a double feature).

With big time movies, the movie production company could provide one or two generic ads with various small variations (like a character from the movie being shown or being promoted with a earlier trailer sitting down next to someone in a theater "watching" a trailer who says "I clearly got here too early." to which the character says "That's why took the time to stop by the concession stand" and waves his box of Milk Duds (or other item from the concession stand) while holding a drink in the other hand.

I think there are so many ways to make advertising less annoying. However, even with no repeats and interspersing ads with trailers and shorts (possibly with some product placement, i.e., subtle advertisement), twenty five minutes sounds painful. Entertaining, or at least mildly interesting, advertisement also requires more effort and some appreciation of the audience. Why bother when one has a captive audience? Even with good targeting information, there is also the problem that those wanting to buy the movie goers time/attention may not be selling something of interest (though I could enjoy a clever car ad even though I do not drive and have a slight anti-car bias). With low effectiveness of ads (and so selling price), their number would be increased to compensate for individual ineffectiveness even if the theater is not especially greedy. Driving away movie goers with more ads, then means even more ads need to be shown to compensate for the reduction in eye count.

I have not gone to a movie for about a decade — Interstellar, which was released in 2014 — and I did not really enjoy the experience. Beside problematic aspects of the movie, the sound volume was not comfortable, the social environment was not comfortable, and I went because my host family urged me to go. However, there was not a long feed of ads, so that experience was relatively good. Anyway, I may not be the best person to ask about the contemporary movie going experience.:-)