Yes, technology is limited by physics, but by many measures it's still very far from the limits. We build tons of things out of steel, ferchrissakes. Computers

Yes, technology is limited by physics, but by many measures it's still very far from the limits. We build tons of things out of steel, ferchrissakes. Computers use many orders of magnitude too much power, even neglecting reversibility. They don't even use the third dimension!