Okay, now solve for local transportation and create a single network that's highly optimized for both long distance, medium distance, and last mile solutions. Bet you it looks like cargo trucks, buses, and road infrastructure.

Sharing because I was delighted to learn this: trees are also an example of convergent evolution. I'm personally rooting for us to become trees. Pun intended.

If trains were optimal, they'd have pincers.

So what you're saying is the optimal form is some kind of crab train?

Minimum rolling friction by having hard wheels on a hard surface. Minimum wind resistance by making it long and narrow. Minimum stop time by having big doors.

BAM: train.

Well if every vehicle becomes autonomous then isn't that just a large scaled high speed train?

Ha! I was thinking along these lines reading science fiction the other day. In every novel where stuff has to get moved overland, it's always a train. No matter their tech level, trains are the simplest, most efficient solution.

Do you hear that, Mr. Anderson? That is the sound of inevitability.

This is just the AI bias showing through: It's all that training.

Even the slime mould knows it: https://www.nationalgeographic.com/science/article/slime-mould-attacks-simulates-tokyo-rail-network

"we heavily biased the network against trains and now it's just saying the optimal car consists of several metal struts connecting just two thinned out wheels that the driver sits on top of and propels themselves using pedals. It was busy redesigning intersections to have clear safe lanes for these bi-cycle 'cars' with plenty of trees / room for pedestrians when we pulled the plug..."