And yet some of the audience ignored all that entirely.
In my particular theater that didn't happen since my family was 60% of the audience (well actually my wife kept getting up and doing stuff until I reminded her we were in a theater) but yeah I've heard it happens a lot now.
I think if theaters want people to keep coming, they will need to make the experience better than home, and that will include enforcing no phone/no noise rules.
I went to see Top Gun a couple weeks ago, it was my first time in a theater in years. There were five different ads, the gist of all of which were, "Don't forget you're in public, so don't talk or pull out your phone or get up if you don't have to". One of them literally said, "We know it's been a while since you've watched a movie in public, and maybe you've forgotten how that works".
It was sort of condescending but at the same time I totally get the need.