I doubt that a car is less expensive the majority of the time, considering cost of petrol, cost of car rental, cost of parking, cost of tolls, and lack of parking in many areas. Then factor in the time difference especially on high speed routes and the car isn't the clear winner or even a close competitor for much of the time.

I can travel in First over a distance of 900km, saving at least 3 hours by train, for a cost of €19-29. Via Michelin estimates the petrol and toll cost at €119.

And one absolutely wouldn't want a car in many major urban centres, such as Paris, London, Rome, Venice, etc. Public transport is also commonly quite good in tourist areas, for instance in Upper Bavaria the OBB network is a viable alternative to driving.

While a car may be a convenience for certain types of holidays, it definitely doesn't come out to be less expensive in general.

I try to walk as much as possible in addition to going to the YMCA 5 times a week. I loathe having to drive. I think that one of the reasons there is so much obesity is due to the fact that some people hop into a car for even the shortest distance.
When my kids were in elementary school which is only 2 blocks away, I had a neighbor who would drive her kids there regardless of the weather.

I prefer walking and do not have a car. Work is 30-40 minutes walk away.

We had that too. We would sometimes take it in turns to collect the kids from kindergarten/nursery and her kids used to go nuts if it was my turn as they knew they would be walking the whole ten minutes. Unless we caught the pedestrian lights on green , then it was only about seven minutes.

I can't believe you made those poor kids suffer.

Mean Old Mandolino, that's me.
My kids walked to primary school, secondary school and then Uni pretty much every day.
But are they grateful?

Same here.

As long as I've got the right shoes, I can go pretty far. While traveling if the area is safe and the weather is not some kind of storm, I'll go 1-2 miles without batting an eye, sometimes more.