There was a time not long ago when subways had those free newspapers ("Metro" etc), and people would read them (and they would clutter the place).
What's wrong with people being on their phone though? I barely use my phone, but if I'm in a tunnel and there is nowhere to look, yeah, I'll read a book, online news or email. I rarely socialize on the subway and I have one of those glances that make people uncomfortable.
Anecdotally: I just came back from London. Big fan of the new Elizabeth line. The Piccadilly (and most lines) low ceilings are a bit soul crushing (I'm tall, but I suspect for most people too), although I really like the character of the old stations.