That is barely even the start of what we need. It would do us better to embrace public transit and densification. If we all just switched to small cars instead it wouldn’t solve the underlying issues with car dependent infrastructure. We’d still have wide swaths of useful land buried under miles of concrete and asphalt. We’d still have urban spaces that are hostile to anyone not in a automobile (admittedly somewhat less so). My commute time is nearly doubled simply because all of the parking lots I have to walk through. There’s no need (outside of accommodating drivers) for everything to be separated by so much empty space.
Yeah, changing up cars seems like scratching at a symptom rather than the problem. If there are thousands of cars all headed in the same direction every day… It seems like offering a train would be pretty obvious win.
Cars would still be needed in some situations though, in which case it would be better if they were small
Trains are great for getting from one dense area to another. As soon as you need to go in any other direction though you are stuck. Plus the US is so spread out you still need a car to get to the station unless you live a mile or so near it and that is a pretty limited area.