I say this as a local who has gotten into countless arguments with friends and family on the subject. I probably believed it as well a few lifetimes ago before I moved to NYC for 13 years and have since been completely converted.
It would require an enormous investment in public transportation and real bike lanes - I mean protected bike lanes like they're doing in NYC, not two faded white arrows in the rightmost lane - and then a generational shift where we convince the younger generations that car-ownership is overrated, wasteful, and terrible for the local economy.
But Americans care too much about comfort and convenience to do that. SUVs rule here.
You would then want to drive as far as you can, park, and take the alternative in.
It's made for people that don't live walking distance from a train/bus line, but also don't want to deal with the traffic/cost/overall hassle of going by car end-to-end.
There are 80 Park‑n‑Rides throughout the my metro area.
From Wikipedia: "There was a dense system of inter-city railways in the United States in the late 19th and early 20th centuries, but after the decline of passenger railroad in North America in the 1960s, the inter-city lines decreased greatly and today the system is far less dense."
Wisconsin used to have inter-city rail servicing most/all of its population centers and even many of the smaller towns: https://www.loc.gov/resource/g3701p.rr006200/?r=0.514,0.298,...
Yes, today cars are the default, but that took a long time. Things will continue to change and it's hard to predict exactly how.
Don't assume that every place is like the place you know. Visit the US, particularly the Midwest, and you'll come to understand why privately owned gasoline-guzzlers are the only solution to this particular transportation problem. The major cities are too dispersed with countless small population centers between them for any kind other kind of transportation to provide a feasible solution. It's not a matter of "engaging in democracy."