Personally if I had experienced that I would just take my business elsewhere. Companies will keep pushing boundaries like this if the worst outcome from them is that for some customers they won't be able to extract the additional profit.

Just tell me when the movie starts, not when the ads start.

There’s movie theaters that do that, Alimo is the chain near me which does.

by your account roughly 20-30mins in. You could also just sit there and read a book while you wait.

That's what I do! I wear a 10K lumen headlamp and read my elephant folio of Finnegan's Wake aloud, so everyone can enjoy it!