My point is simple: in a future of resource scarcity due to overpopulation, needed mass relocations and supply chains reorganizations due to climate changes there is already and there will be no room for cities and trains. What's there will remain of course for longer, becoming a bit at a time a receptacles of poor and desperate who do not see nothing outside their bar-less prisons, a thing we can already witness in vast part of the world.

Specifically:

> That's exactly what a locomotive is. The shinkansen trains don't have them. All the cars have motors and propel themselves.

Ok, shinkansen have self-propelled wagons, I do not know for sure but TGV definitively not and I'm pretty sure most trains in Japan are not self-propelled for all wagons, as in the EU.

> Cities are very sustainable, that's why humans have been building them and living in them for thousands of years now.

Things changes, are have always changed. We have had urbanization and deurbanization cycles but what's different was the tech, now we have TLCs, IT, fast logistic a thing we haven't had in the known past. Meanwhile we are more and more, too much for high-resource intensive big stuff like cities.

> Cities are the engines of any modern economy.

Yes, but less and less. With the first globalization factories pull out of rich cities to go to cheap countries, with remote works there is no need for offices and as a result there is only a kind of unsustainable economics in cities: service industry to humans that are poorer and poorer. Cities are need by modern financial capitalism because you do not want self-driving taxis, uber, just eat and so on outside the city, but such form of economical and social development is at the end, being oppressive and unsustainable, consuming way too much resources for the planet.

> And no, you don't need to move passengers 24x7; most people sleep at late hours so you can shut things down at those times and let the few people who need to travel use other means.

That's what happen today and that's one of the reason of cities inefficiencies. BTW just imaging how ABSURD and inefficient is in modern times having big buildings which demand big infra around to use them for less than 12h/day commuting between them just to consume services and being exposed to physical ads in various forms.

> Trains and buses here in Japan are not under-utilized at all. Cars are, but that's a problem everywhere and one of many reasons people shouldn't use them so much.

To be tied to someone else service, right? So enslaved by conformism and other services will and design. A notorious tract of any dictatorship notoriously ending in deep sufferance and disruption. Cars are needed because collective transportation means can't substitute them, BUT, cars can substitute collective transportation means, that's why a SANE economy choose to ditch other transportation means.

> No, it really isn't, thanks to basic physics.

That's not what WEF say and not the path we really took mostly silently preoccupied by people reaction not by technical feasibility https://www.easa.europa.eu/sites/default/files/dfu/uam-full-... and if you really think despite the name it's clear that there is nothing "urban" in density and tall buildings terms for such mobility, if you go further you'll notice there is no possible green new deal future for dense area because we must re-made them from scratch a thing possible with big issues for a single building or a small area but not more and you might know that all future city projects, like Neom, Arkadag, Innopolis, Telosa, Prospera, are failed as the original Fordlandia because their model in untenable.

For Japan: do you remember the Shinkansen blocked in a plane fully exposed to the tsunami due to it's central command model? Do you remember Tokyo emergency coordination failed due again to a central design? Japan is in deep trouble as we are, because of the city-centric development, it's about time to try a totally different model possibly before the WWIII witch we will loose anyway.