I have a 30 minute drive to work - by public transport it would take approximately 1h 45m each way. Added to that, the nearest bus stop is around a 15 minute walk away which with my physical issues would take me nearer half an hour. By the time I got to work I would be very tired, let alone having to repeat the journey coming home but as it is I arrive feeling fresh and ready for the day - having uplifting music on and able to control air flow and temperature in the car can really affect any tiredness I may feel.
If I were working shifts at the same place, there would be zero public transport in the small hours. There is no way I could afford a taxi for the journey even when it's not unsociable hours, which tend to cost more.
These are similar commutes for many of our critical services workers; not just nurses and doctors but the admin staff at hospitals, the public transport drivers getting them in, the on call engineers who need to fix critical equipment (imagine trying to get public transport at 3am to fix someone's life dependent equipment!), manufacturing workers, bakers.....
As pp have said, living today has become dependent around road transport including cars, vans etc. We can't go back to the days when everything was just in one small area, and TBH I'm sure if they thought about it people would realise that the inconveniences wouldn't be worth it e.g. less availability of items, higher prices, few or no deliveries, thousands of tiny cottage hospitals would be unable to deal with much more than minor injuries, loss of the economies of scale from centralised manufacturing....