My village has about 300 people in it, so call it 300 return trips per day.
Those trips might be east to the small city. Or west to the mid-sized down. There's a bus in those directions, about once every 2 hours, last one at 6pm so useless for evening activities, or commuting further on the train. It's just gone past my front door now, it's rare to see more than 2 or 3 passengers on board other than at college time.
My options for going further - to London or Manchester
1) bus to the station, train to london, tube across london, then return on tube, train, and get a taxi back from the station
2) drive to the station in the morning, park, drive back in the evening (last train arrives about midnight)
3) drive the entire journey, under 3 hours so about the same amount of time
Same if I go to Manchester and Birmingham, but the drive is about half the time of public transport.
They might be south towards the big village. Or north to another big town. There's no bus services there.
Now you might say "just put on more public transport". My wife drives to work at a hospital 25 miles away. I suspect you could meet the entire daily demand from my village in that direction with a single minibus. The route doesn't pass any other major settlements, it's south-west down the lanes. How frequently would a bus need to run to be useful? Every hour? How early would it start? How late would it run? How many people would it take on each journey, and how much would it cost to run? How much pollution would it cause? What benefits would there be?
Public transport doesn't work below a certain density. If you want to depopulate the country and put everyone in tower blocks in the city - leaving the country for the rich - then just be honest about it.