I don't think the US is a lost cause. I think about 80-90% of the US shouldn't be the focus of smarter urbanization efforts, but that's because 80-90% of the US is sprawling farm land.
I'm seeing sentiment shift around cars, bikes, and public transit. I had a discussion at work the other day and three of five people said they would much prefer public transit or biking to work, it's just not viable with today's options. I think local effort can and will spread the message. "If Springfield can do it, Shelbyville can do it better" needs to be our aim. Things like national high speed rail networks are just too big to start until the ball is already rolling.
It's even more than 90% of the land: 80% of people in the US live in just 3% of the land area. The only infrastructure needed in 97% of America is just train lines stringing small towns to the nearest big cities. We used to have this. The train tracks are mostly still there. We just need to make a deal with railroad companies that we'll invest in the tracks in return for national passenger trains having total priority on them. Or just eminent domain them, that would work too.
As a train nerd, I'm 100% on board with "nationalize the rails" and use a similar licensing system as we presently use with trucking and open up the rails to private companies whose equipment meets FRA + Amtrak standards.
With the rails being publicly owned railroads only have to foot the bill for vehicle maintenance much like truck companies do, and it puts railroads on an even footing with truck companies for price competition. There's always the challenge of investment in new lines, but that can easily be managed with a set exclusivity period, say "10 years exclusive rights for tracks you construct yourself" with requirements for maintenance, require FRA approval to remove the tracks within that exclusivity period, and require allowing non-competing passenger services and through trains (with of course very explicit language for what counts as "competing passenger services" since a once a week passenger car shoved on the end of a local freight train that goes from nowhere to nowhere shouldn't count as competing with hourly intercity passenger services)
Biggest for me is that publicly owned rails would allow for much more impressive excursion trains and more extensive routes that come much closer to home