I think it's more helpful to think of it as there are physical limits, so we approach an asymptote. Sure, if we had cheap fusion or room-temperature supercondu

I think it's more helpful to think of it as there are physical limits, so we approach an asymptote. Sure, if we had cheap fusion or room-temperature superconductors, that might be game-changing. Barring those, I'll take 1%/year improvement for 100 years or more. For example, you're not going to see supersonic flight again due to the parasitic drag (physics) requiring so much fuel. You could make ICE engines twice as efficient by cutting the car weight in half. Municipalities had this great program before - swap your old fridge or water heater for a free, more efficient one. Maybe have Amazon ship your items to a community mailbox without the brown box? Those are doable things that pay benefits immediately.