Trouble is, so many people in built up areas have to pay a lot of money to commute jam packed in trains - google London Underground/Tube in rush hour images. All the time, you're breathing in PM 2.5 at a high rate (Now You Know used PM meter 2.5/10). travelling by car is not a practical option.
I've seen fights to get on to trains in UK, I've seen people pushed out of trains. I've had to use my body to stop a small child getting crushed when the train braked. His Dad couldn't find a space near him but the alternative for them was not getting home that night.
After Covid, small vehicles with air filters, UV cleaning between different passengers seems like a great idea. If TBC can cheaply dig tunnels to increase capacity, add more cars in staging areas and just have point to point travel rather than stop-start-stations, the experience will be much better. I really think this can take off. I look forward to above ground being for pedestrians and some cyclists with underground being most of everything else (including some cycleways).