Really? I see this all the time. Maybe I'm going to all the wrong places. I see "couples" on their phones, I see groups of friends on their phones, etc., etc. Maybe different parts of the country / world?
I don't see the problem; when you're out drinking with buddies, sometimes you're talking and sometimes staring at the sportsball TV in contemplative silence. Or a phone instead of the TV, it serves the same role. It doesn't have to be talk all the time. Somebody who's not talking now might have been talking a minute ago, and will be again in a few minutes.
If you're all staring at the TV, you can at least share your thoughts on the thing you're all watching together. If you're all staring at your phones, your minds are in different places. It doesn't serve the same role at all.
NYC here too, I'm not sure where you're going but go to any sports or Irish bar and >50% of the people there will be on their phone, especially when they're solo. I do wish I could read a book, but so many bars keep it so dark even in the daytime that it's impossible these days.
People go out by themselves all the time (I'm single, WFH and live by myself, if I didn't go out by myself I would literally leave the house only once or twice a week).