The lasting infrastructure of railways was the rights of way and the stations, and I think you're hinting that building them in the 1840s allowed us to do that when no one cared very much about NIMBYs or bulldozing through the countryside.

What's the corresponding infrastructure of AI? The major cost - the GPUs - are effectively obsolete after 3-5 years. The physical location of the datacenters, power, cooling and fibre that connects them might be the lasting infrastructure. Is datacenter location important? Are we actually building up new power sources (apart from endless announcements about FANGs opening nuclear power stations, which as far as I'm aware have not happened yet)?

I’d look to the lasting infrastructure improvement from the dotcom era. Such as laying fiber.

A big ones here may also be increased technological literacy, the rise of a new UI paradigm (chat with a non-human) and the structuring so much data in the world that while it previously existed was hard to meaningfully leverage because it was unstructured.

And, last but not least, lowering the barrier to entry to starting tech companies by eliminating and launching a new generation of SMB-like tech startups that don’t need to take VC-money and scale to survive. And as a result can can solve problems facing niche industries (not to be confused with things like Wix or Etsy that lowered the barriers business selling real world products to create an online presence)

If nothing else, mainstreaming AI will have the same impact mainstreaming spreadsheets did.