Ah - a newbie :)

90% was just a number for argument. The impact could be significant, though. The effects are unknown. And it it takes out enough jobs to create a deflationary depression then a lot more jobs could be lost as a result of the depression. There are a lot of unknowns.

Look at it another way:

We assume the unit cost of laying tracks is the same, and that some track can be shared for country B. We also assume GDP is the same for both countries so the important statistic is length of track only

Square country A has two major cities, each of population P, which are located at the opposite corners of the square. The area is X^2. The distance between the cities is sqrt(2)X.

Square country B has four major cities, each of population P, which are located at each corner of the square. The area is X^2/2. The minimum required line to connect is about 2sqrt(2)X/sqrt(2), that is 2X

Granted, it's a simplistic analysis for illustrative purposes but shows that the balance of costs isn't necessarily the way you are assuming - that is it's actually probably more expensive for Europe. In this example, the larger and more sparsely populated country has to spend 1.4 times as much. This ignores revenue from ticket sales, of course, So let's assume that it's twice with twice the population, now the larger country spends 1.4 times as much per ticket sale. But that's not 2.5:1 as you are suggesting as the important ratio. Given that USA:EU GDP is 3:2, the 1.5/1.4 is 1 - i.e. in proportion to GDP it would be a wash. Obviously, the exact details are different but given that the cost of land is a large part of the cost of building rail links and land is cheaper in the USA, then it's not obvious that it should be hard for the USA to build high-speed rail if it wants to.

You are saying that the policy was created by Merkel. I pointed out that the policy already existed. Whilst Merkel may have restated it in slightly modified form, it was already there so laying all the blame on Merkel is historically inaccurate. Is that clear enough?

Per capita GDP of USA:EU is 2:1. So the USA should be able to solve the issue as it is much wealthier, near 'total dominance'. The failure to solve it is due to political will, not ability to do so. Given the wealth disparity, the geographical disparity isn't insurmountable.

My focus was never solely high-speed rail.

And has zero bearing on the debate.

Denialists use the trope "the climate is always changing" to undermine the case for there being climate change at the moment due to human actions. If you were genuinely interested in preventing anthropogenic climate change you would know this. This is why I am calling it out. You use a number of tactics to try to undermine the consensus, such as this discussion and reference to climate-change deniers in favourable terms and the calling out of unnamed "environmentalists" for stopping progress. These are all hallmarks of denialists, and I've been around the scene for decades and have seen it all, including denialists trying to couch themselves as "friends" to then sew doubt, much as you do.

You tell me what is special about him, as you are the person that previously referenced him in glowing terms as a founder of Greenpeace (he was not) and a supporter of nuclear power but leaving out his extreme climate change denialism.

The taxation can come from various sources, and not all of those sources are natural people. There seems to be an obsession with it coming from people but economic activity is about transformation which doesn't necessarily need people. Examples are transformation of seeds, soil, sun and rain into food, oil under the ground into miles moved, blank paper into art. We tax a mix of entities producing the transformation. If those transformations are still done then we can simply change the entities.

Most people currently have enough income to meet basic needs. If the economy stays the same size then there must be enough money in the economy to provide for those basic needs. There is only not enough if the economy shrinks. Whether UBI can be implemented without shrinking the economy is the question, but if people get displaced from work and associated income, the economy will shrink.

I have not bought any hype, it's a hypothetical scenario for the purposes of debate.

I think you must be talking about LLMs, as AI is used extensively in a number of ways and in those it is highly realistic - predictive monitoring of engines, bridges, cancer prediction, facial recognition, bank fraud detection - there's a very long list. Don't confuse LLM and AI.

I have a research background in AI, and 30 years ago AI was more primitive. It has improved. It has generally, to this point, served as an adjunct to jobs or to provide insight into datasets that it is not likely people would have funded people to do. However, just because a tipping point has not yet been reached does not mean that a tipping point does not exist. Already, this month, we've seen that it's possible to replace people writing dull, 1970s-style soft country-rock with AI

It's not about labelling it. Where it comes from and how it is done is important. If it wasn't, then we wouldn't have graduated income tax rates.

Many things can be taxed. It doesn't necessarily have to be wages. Indeed, wages is just one of the things currently taxed and rates of tax an various activities can be (and are) modified.

You're not really providing any objective evidence, so this is just an opinion.

Did you know what before there was a rail line across the USA, rail traffic between those points was low. OK, I am being a bit facetious, but transport links encourage usage and associated economic activity, which is why the US government supervised the transcontinental links. If there is likely to be insufficient traffic and no likely economic boost, then sure, don't build it. And yes, I am lumping in freight too, as just because you have a high speed link doesn't mean you can't use it for freight, and it doesn't all have to move at 250mph provided you have passing places and orchestrate high speed traffic around low speed. Marshalling fast and slow around each other happens all the time in Europe, although that's more common with standard lines than the high speed ones.