Roads are much cheaper and more useful. They can be used for moving freight whereas good public transport keeps freight off the lines to avoid timetabling problems caused by blockage.
The interstates in the US alone have costed more than 25 trillion dollars. That's just the interstates, no other highways or roads.
But none of that even considers cost of using said roads. In the US, on average 15% of gross income is spent on automobile transportation.
That's a 15% tax right off the top, before your other taxes.
The reasoning of "we spend a lot of money so it must be good" is just bad. No, we spend a lot of money on stupid shit all the time. Both historically and currently.
Americans spend on average 15% of their gross income on automobile transportation. That's not including their taxes that went towards said automobiles, roads, and oil.
Nobody actually wants to do that. If you could get to work without an automobile, you would. But you can't, can you?
Automobiles are parasidic in nature. To work, they require vast amounts of space and sprawling urban design. But when you get said vast amounts of space and sprawling urban design, then automobiles are the only thing that makes sense.
We have a car centric built environment because people have rationally decided for many valid reasons that automobiles are the best way to get around. It's not because they are "parasitic", whatever that means.
Note that a large part of why cars are better is the network exists. If you had to drive on dirt (not even gravel!) roads that became impassible when it rains you would call cars a bad way to get around. However the road network is such that you can nearly anywhere in a car.
Also, they should do this without crippling cars, since that would be far easier to do than producing a compelling alternative to them as they currently exist.
Do you mean without continuing to give them 99% of available resources? Cars are by far the most privileged form of transportation worldwide. We bend over backwards to subsidize them as much as possible at all costs.
So of course, any attempts at clawing back at least some of that privilege are met with outrage, e.g. bike lanes.
I don't know if cars are subsidized more than mass transit on average. It's quite possible they are. The overwhelming majority of people find cars much more useful and enjoyable than mass transit, and politicians have to provide people with what they want to some degree. It's not a conspiracy of the oil companies.
EVs are changing that because they don't pay fuel tax. So, governments are now proposing to change how vehicles are taxed to make the roads pay for themselves again.
The USA is different to Europe because gas taxes are a political live wire there in a way they just aren't in Europe. Presidents win campaigns by promising to reduce the price of gas! So of course the road network is in deficit there, it's a populist move. The equivalent populism in Europe is to make public transport free instead, as the governments are more collectivist minded there, whereas in the US personal freedom is a major concern.