What do mean by "they"? EDIT: who do you mean by "they"? (Rephrasing since some readers don't get that intent of the original question.) The handful of corporations interested in transport? Roads were a broad-based need. Roads have been built, used, maintained for thousands of years. The interstate highway system came from a government initiative, if there was a "they" it was broad-based enough to be "us". Railroads served needs that had existed for a long time and it was very clear what their use was from the time they were conceived, and there were more than a handful of participants in the movement of goods and people, since producers wanted greater reach and consumers wanted better access. By contrast to the very small number of "they" asking for more elecricity for data centers. How many people involved in the discussion are asking for the AI companies to be getting this juice?

Can you believe these “mammals”, burning energy around the clock to keep their blood warm all the time?

No, but there really should of been. We've largely been conned into accepting a highly un-scalable transportation infrastructure by the automobile and oil industry.

In the 60s there were, and they were right: https://en.wikipedia.org/wiki/Highway_revolt

OP is saying the opposite: the TCR required huge investment, and was massively speculative, with a huge bubble ensuing. But rail travel did revolutionize the world, and few people sat around asking whether or not it was worth it.

TCR could have been justified by everyone having massive faith in the future, as OP is suggesting happened with roads. But you're quite wrong that "few people sat around asking whether or not it was worth it", as Iron Empires details:

https://www.amazon.com/Iron-Empires-Robber-Railroads-America...

it was hugely controversial in Congress.

I don't happen to know about roads, since that wasn't one single thing. But I doubt they happened because of blind faith in the future, either -- it was probably more businesses demanding roads NOW. So the argument that no one questioned them is dubious at best.

Sorry, you are correct. It was controversial.

What I meant to say was that the AI bubble is feels different in that there seems to be relatively more skeptics versus railroad mania or the dot com bubble (but this could just be skewed by my own experiences).

Whether or not this suggests a flawed value prop for AI is another story.