> Most technologies do not follow Wright’s Law – the prices of bicycles, fridges, or coal power plants do not decline exponentially as we produce more of them.<p>I would bet Roser is wrong here and he can't provide a reference for his claims here. I'd predict that they <i>do</i> decline exponentially, it is just that (1) we have already produced a huge number of them so it's hard to observe the next doubling of cumulative production, and (2) the learning rate exponent is a lot worse than in the more obvious examples like solar panels or deep learning.