Cars are better than mass transit in a low population density place. In a high population density place like Manhattan you wouldn't be able to get enough cars to fit on the streets if everyone was in a car. If you used buses you might make it work but not cars.
So you're right about Denver but you made too much of a blanket statement.
The reason the majority of people in cities favor investing in mass transit is in the hope that other people use it so they can continue to drive and enjoy less traffic and more parking.
In ten years I don't expect there to be many place I'm going to bother taking a train in. Tokyo's are good enough, but that's a high bar.
Uber already spoils me too much to want to take the subway on Manhattan (crossing the river is a different story).
A data point countering your assumptions - I sold my car because I don’t like driving. I want transit to be good so I can use it.
This might describe you, but I would be extremely surprised if it actually described a majority of people... Especially in cities with high ridership (NYC, for example)...
I only said that you were wrong in your assumption about people's motivations in supporting mass transit. If you're in a city (especially in one with high ridership, like I said) mass transit expansion can be hugely impactful and not because you'll ever be able to drive a car...
Obviously there are many additional costs associated with driving in NYC...