I don't go very often,
specifically because of people eating, nothing else.
Honestly, what is wrong with some people that they can't go two hours without eating?
I was heartened by a report last week that said one of the smaller cinema chains is introducing food-free showings.

I'd like to think the big chains will follow suit, but given that their mark-up on popcorn is such that a £3.50 tub costs them £0.07, I doubt it...

I do notice some of the films being out of focus too, by the way.
Although it is very firmly the food issue that stops me going more often.
If I do want to see a film, I try and go to a weekday showing, early/mid morning.
Less people and certainly less chance of people eating popcorn.