Simply put, it’s not as easy to build transit or pedestrian infrastructure as roads. That’s it, at least in the USA. There’s an endless money machine for road maintenance and widening and anything car related and there isn’t at all the same for anything else.

So the public transport barely exists anyway and even if you give them a park and ride they won’t use it because public transit sucks and is far less enticing even if bike lanes nuke car lanes.