I've rarely "shared" it with other people in any meaningful way.

I almost always hear other people talk or see them using their phones though, unless the cinema is pretty much empty.

Ah! Sounds like a great idea, a cinema followed by some cocktail party for people to talk about the movie. I'd go to that sort of event.

What you describe has also been going on for nearly a century, at least in Europe: movie (and ordinary) theaters with a foyer (anteroom?) were people drink, smoke (in the past, but also now in some countries) and socialize before the movie starts and during the intermission (a short 10-15 minute break splitting the movie in two parts customary in some countries so you can piss in peace, have a drink or a smoke back in the day, and restock on popcorn without missing anything).

And that's for regular movie screenings -- there are also all kinds of organized screenings, where people get to talk and discuss the movie afterwards, especially for art films and such.

But already being in an audience while the movie plays, and being aware of people's reactions etc. is a shared experience (and it had been alluded as such by tons of filmmakers).