Earlier quoted context omitted.
Apple produces one A series chip for the iPhones every year. How does that work?
Look at the Apple A12x. They disabled a GPU core in it for the iPad, and then in the A12z they enabled that core. This was likely to help with yields. Then with the M1 chips they decided to sell a 7 core version of the chip with the base level Macbook Air and save the 8 core version for the higher trims. Even Apple is susceptible to it. But Apple doesn't sell chips, they sell devices and they can eat the cost for som…
Being able to sell bad batches of product takes some of the sting out of failure, and past a certain point you're just enabling people to cut corners or ignore fixable problems. Having a tolerance of 1 bad core means if I think I have a process improvement that will reduce double faults but costs money to research and develop, aren't I more likely to get that funding?