I was in Philadelphia for a week and also used my commute time (2 hours in total each day) to program. As a web developer who uses Github Copilot and often checks documentation online, I did not have such a good experience as OP had. Mobile data is pretty much nonexistent in Philadelphia in the subway and there are also no wifi Hotspots. Sure, it was better than nothing, but I would quite often find myself waiting for the subway to arrive at stations and hoping that there is at least some internet connectivity there.