In silicon manufacturing, the inefficiency is actually pretty low specifically because of the kind of binning that Intel and AMD do, that GP was complaining about. In a fully vertically integrated system with no desire to sell outside, the waste is realized. In a less integrated system the waste is taken advantage of.

In theory capitalism should broadly encourage the elimination of waste - literally every part of the animal is used, for instance. Even the hooves make glue, and the bones to make jello.

Apple probably does the same strategy PS3 did: create a 1-PPE + 8-SPE chip, but sell it as a 1-PPE + 7-SPE chip (assume one breaks). This increases yields, and it means that all 7-SPE + 8-SPE chips can be sold.

6-SPE-chips (and below) are thrown away, which is a small minority. Especially as the process matures and reliability of manufacturing increases over time.