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 see single people use their phone while they wait for their date/friends to arrive. Or while their date uses the restroom.
I see groups of friends where one person is temporarily texting because the babysitter reached out, or a friend is asking where they are, etc.
Going to restaurants and bars is expensive. People aren't going out to use their phones.
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).