I’ve used public transport for 52 years (I don’t have a car.)
I read (I don’t have a smartphone.)
Here in the UK, you usually don’t talk to strangers.
Back in my younger days, I took the bus to college and work fairly frequently. Depending on the day and time, I’d read or study, or take a nap, or talk to the other passengers. There was a pretty steady group of daily riders, and we became rather friendly over time. I rather enjoyed it. Now that I pretty much take a bus or train wherever I go, I miss the conversation time.
Another long-time BART rider here…
Back in the 90s, people either had a book, usually paperback, or the newspaper. Concord to Powell was a good amount of time to get through the Chron, and in the evening, I’d grab an Examiner to see what happened during the day, and for the crossword.
Around the turn of the century, business laptops were coming up in the world, so you’d see lots of people working on Word documents or emails.
When Harry Potter hit the scene, it seemed like every other person had their nose in that book.
Then, when the Kindle came out, every other person had one. I still see the occasional Kindle, but phones and tablets have almost completely replaced laptops to the point it’s weird to see someone working on a laptop.
Reading a book, mostly. If it was an elevated train, I also liked looking out the window, especially on the way home in the evening.