It is not. Car infrastructure is some of the most expensive there is. It’s cheap because it’s heavily subsidized.
The subsidisation argument is one that occurs quite often. I can only speak about the situation in my country, Germany. Since every citizen is dependant on car infrastructure, due to their dependance on Trucks transporting goods into the supermarkets, Police service, Ambulances,… and especially they are in need for this infrastructure, because it is used to build the houses people live in and it is used to maintain these houses.
So everyone in my country is somewhat paying for car infrastructure, totally independent from their use of it for private transport, because they are indirectly in need of it. This is what is commonly called subsidisation for car infrastructure, because the use of the capital is often not directly declared by the government.
Now car owners, that drive, have to pay an additional automobile tax, because as it is with all cars, they slowly wear out the road and repairs need to be paid. Due to their additional use of the roads, they have to pay additional for damages and repairs.
It’s popular because car manufacturers made it popular, with propaganda and lobbying for making cars the default form of transportation.
Nah, it rly. Railway companies had their chance. And they failed. Railway companies in the past were extremely rich, they had to capital, but Cars by themselves were at one point considered the better, more efficient, way of transport. So we ended up in a situation, where worldwide rail infrastructure is only used for niche solutions. For example on extremely long trips, to replace planes. (Planes are indeed extremely subsidised which our much logic. But maybe I am just uninformed and kissing the point considering planes).
If your opinion is the obviously correct one where driving is the only thing accomodated for, why does the actual data show that the model for walkable cities with good transit have happier, healthier, more comfortable people, and are economically stronger than car dependent cities?
Now I am rly interested in the subject. Maybe you can tell me where you heard that, or maybe you even have a link? Secondly: A city should accommodate all means of transport. A modern city also includes public transport, a few well placed trams, flexible bus lines, cycling infrastructure, and good pathways for pedestrians. But also parking space for cars.
A modern city is welcoming to the new. This also includes scooters, bike sharing, car sharing, EV, and so on.
And addressing the point of a stronger economy, I highly doubt that economic strength is dependant on 30 meters of rail, 10 Meters of Asphalt or whatever.