Having good public transportation that everyone uses shouldn't be about shaming them into using it. It should be used by everyone because of how easy and convenient it is, and safe. They should look at the traffic in disgust and prefer an easier alternative. I don't even care if people still drive some. There are just some places you have to go where you're going need a car or some errands that are going to require one. Plus, it's ok to drive sometimes, but we do need a good alternative to relying on cars for transportation so we can ease traffic congestion and not have to constantly rely on cars for it.
My paternal grandfather rarely drove. My dad's side of the family is from Germany. My grandfather had a brand new Chevy Bel Air back in the 60s, and it just sat in the driveway all the time. My mom said he went down to the dealership, bought the car, had my uncle drive him home in it, and he never drove it again. My grandfather worked on the UT campus. He walked to the bus stop every day from his house in South Austin, and then took the bus into work and back. And this was back in the late 50s to late 60s when much of South Austin was still mostly rural in spots. All of my aunts and uncles and oldest cousins also took the bus in their youth. My oldest aunt on my dad's side of the family didn't get her driver's license or a car until she was nearly 40 years old. By that time she had already been in the US for nearly 25 years. They all grew up in an urban environment that allowed them to use public transportation. My grandfather also rode his bicycle to work in Germany and relied on it for errands. My cousin says he probably rode his bicycle 50 miles a day. And they had 4 kids at the time, so it wasn't like he was some young guy with no worries or responsibilities.
Now a generation removed from that time, and nearly everyone, even young people, rely on cars. It's not even so much because of our built environment, although, sidewalks are a must even if you don't have dense housing. As long as you have sidewalks, bike lanes and public transportation, you can still get around without a car. People aren't going to walk or take the bus if those situations are sketchy. Americans have become born into comfy environments where they expect a certain level of convenience. Unfortunately some areas, even inside the city, don't suggest that it's safe to walk.
By the way, the talk of fuel efficient trucks reminded me of something I read recently - Ford makes aluminum-bodied F-150 in factory Henry Ford built.