Why Does Ezra Klein Say the Physical World Rate-limits Artificial Intelligence?

Ezra Klein says the economy will be very jagged because things have to happen physically. Buildings need to be built and transmission lines need to be laid down, and the physical work has powerful rate limiting, so it cannot accelerate as fast. Inside the digital world, things can move very, very, very fast.

He says white-collar work done completely on a computer can be automated, including work in a call center, and so can cyber crime and cybersecurity. Most of what would improve people's lives has to happen in the physical world, but AI will move fastest in the digital world. He says the equilibrium might be the world where people get the most harm from AI rather than the most benefit.