I agree, and would take it a step further as I dont think phones are the key issue here. Public places where people are moving through have had people distracted by one thing or another before the advent of phones, reading, listening to music, or just trying to get where they are tying to go, stuff like that. If theres actually something going on, people still put away their phones and pay attention to the thing or activity (though they may take a picture which I dont really see an issue with). 

The larger problem as I see it is that there arent any places to do approaching, as outside of the bars in the example tweet, which still seem to be as viable as ever, places to do hobbies or activities in person where socialization are either nonexistent or severely skewed towards one sex or the other.