In reality, rather than arguing about mode of transport, i.e. the old "car versus bus", what we should be looking at is reducing transport of whatever form. That way we wouldn't be just transferring the costs/pollution of transport from car to bus/train or whatever.
Encouraging/facilitating people to need to travel less is the real answer to the problems. I.e. localism. Get people back to shopping/working more locally and incentive that instead of subsidising public transport.
Go back a few decades and people really didn't travel as much. They worked/shopped much closer to where they lived, and there was usually recreation/entertainment more locally too. Over the past 30 years or so, nearly everything has been centralised, local shops have been closed down firstly by town centre shopping centres, then huge out of town retail parks etc. National firms (banks, accountants, insurance firms etc) have closed down town centre/regional offices and centralised into London and a handful of other big cities. There's been a "drain away" from villages, small towns, etc leaving people with no choice but to have to travel for work, shopping, leisure, etc.
A policy of localism would help reverse that. There were a few green shoots of optimism due to covid, where people started getting things delivered instead of going shopping (but more vans on the road), people working from home, a suggestion that small/village shops/cafes could become profitable again if people worked from home instead of commuting for an hour or two to their city jobs. All that seems to have stalled now and people are reverting back to how it was before, which is a great shame.