I'm not sure about the current state of the art, but microprocessors production is (was?) very bad. You make a lot of them in a single silicon wafer, and then test them thoughtfully until you find the few that are good. You drop all the defective ones because they are very cheap piece of sand and charge a lot for the ones that works correctly to cover all the costs.

I'm not sure how this translates to programming, code review is too expensive, but for short code you can try https://en.wikipedia.org/wiki/Superoptimization