The world could run on older hardware if software optimization was a priority

The world DOES run on older hardware.

How new do you think the CPU in your bank ATM or car's ECU is?

Related: I wonder what cpu Artemis/Orion is using

IBM PowerPC 750X apparently, which was the CPU the Power Mac G3 used back in the day. Since it's going into space it'll be one of the fancy radiation-hardened versions which probably still costs more than your car though, and they run four of them in lockstep to guard against errors.

https://www.eetimes.com/comparing-tech-used-for-apollo-artem...

> fancy radiation-hardened versions

Ha! What's special about rad-hard chips is that they're old designs. You need big geometries to survive cosmic rays, and new chips all have tiny geometries.

So there are two solutions:

1. Find a warehouse full of 20-year old chips.

2. Build a fab to produce 20-year old designs.

Both approaches are used, and both approaches are expensive. (Approach 1 is expensive because as you eventually run out of chips they become very, very valuable and you end up having to build a fab anyway.)

There's more to it than just big geometries but that's a major part of the solution.