[Bartweiss]

> had you built a tractor for a company they would definitely want to know why you want to build a brand new tractor when the old one is working fine.

You're not wrong about the cost and the need to justify it, but I think you might be underestimating how often this happens to physical products. Lists like "the worst cars of all time" are full of needless reworks, frequently driven by some executive's desire to fully "own" a product. I suspect the biggest difference is just that as the cost of throwing away a working design becomes more expensive and visible, the decision to do so slides higher up the ranks.