In my life the people who are the worst about this are in their 50s, 60s and early 70s. The teens I know use their phones around each other and it's jarring to me but stepping back it's still fairly interactive. They are showing each other things, engaging in a drawn out conversation with each other as they scroll, etc. It didn't initially seem like it to me and it's not how I like to interact but they are still socializing.
The older people are putting on their reading glasses and just going completely in, zero interaction with or awareness of their surroundings. A lot, probably the majority of people in this age range don't use their phones for entertainment at all. But the ones who do I think are as bad about it as any stereotype about kids these days.