I’m pretty sure we can comprehend it, we just usually enjoy said freedom of movement in nature on our feet rather than sat in an SUV.
So no, I don't think Europeans who haven't been in America have quite absorbed just how vast America is. It stretches across an entire continent in the E-W direction, and N-S (its shortest border) still takes nearly a full day. (San Diego to Seattle is about 20 hours, and that's not even the full N-S breadth of the country since you can drive another 2.5 hours north of Seattle before reaching the Canadian border). In fact, I can find a route that goes nearly straight N-S the whole way, and takes 25 hours to drive, from McAllen, TX to Pembina, ND: https://maps.app.goo.gl/BpvjrzJvvdjD9vdi9
Train travel is sometimes feasible in America (I am planning Christmas travel with my family, and we are planning to take a train from Illinois to Ohio rather than fly, because the small Illinois town we'll be in has a train station but no airport; counting travel time to get to the airport, the train will be nearly as fast as flying but a lot cheaper). But there are vast stretches of the country where trains just do not make economic sense, and those whose only experience is in Europe usually don't quite realize that until they travel over here. For most people, they might have an intellectual grasp of the vastness of the United States, but it takes experiencing it before you really get it deep down. Hence why the very smart German engineer still misread the map: his instincts weren't quite lined up with the reality of America yet, and so he forgot to check the scale of the map.
There are plenty of city pairs where high speed trains do make economic sense and America still doesn't have them. [1] is a video "56 high speed rail links we should've built already" by CityNerd. And that's aside from providing services for the greater good instead of for profit - subsidizing public transport to make a city center more walkable and more profitable and safer and cleaner can be a worthwhile thing. The US government spends a lot subsidizing air travel.
> So no, I don't think Europeans who haven't been in America have quite absorbed just how vast America is
China had some 26,000 miles of high speed rail two years ago, almost 30,000 miles now connecting 550 cities, and adding another couple of thousand miles by 2030. A hundred plus years ago America had train networks coast to coast. Now all Americans have is excuses why the thing you used to have and tore up is impossible, infeasible, unafordable, unthinkable. You have reusable space rockets that can land on a pillar of fire. If y'all had put as much effort into it as you have into special pleading about why it's impossible, you could have had it years ago.
This is, of course, a massively broad generalization, and there will be plenty of voters who don't fit that generalization. But the average American voter, as best I can tell, recoils from the words "high-speed rail" like Dracula would recoil from garlic. And I do believe that California's infamous failure (multiple failures, even) to build the high-speed rail they have been working on for years has a lot to do with that "high-speed rail is a boondoggle and a waste of taxpayer dollars" knee-jerk reaction that so many voters have.
The forests and wilderness of the PNW are much, much, much, much more remote and wild than virtually anywhere you’d go in Europe. Like not even close.
Or have a "car-cabin-without-engine-and-wheels" and treat it like a packet on a network of trains and "skateboard car platforms".