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 some of these. For example if a chip has 2 bad cores instead of selling a 6 core version Apple is probably just scrapping it.
Having no margin of error on these SKU's would be terminally dumb, but having tight error bars isn't necessarily a bad thing.
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?
All of those device perform exactly the same, as Apple has chosen the same power/thermal set point for all of them. This is going to start to look a lot different in coming years when the larger MacBook Pro transitions - I expect 2-3 more models there. Then when the Mac Pro transitions I expect another 2-3 models there.
We'll start to see high-binned next-gen Apple Silicon parts moving to the MacBook Pro, and Mac Pro, and lower-binned parts making their way down-range.
Another commenter (dragontamer) pointed out elsewhere in the thread that Apple might be doing what Sony did for the PS3 (since Sony also made custom chips that had to perform identically in the end product): the strategy Sony took was to actually make better chips than advertised for the PS3, and disable the extra cores. That means that if one of the cores is broken, you can still sell it in a PS3; you were going to disable it anyway. Yields go up since you can handle a broken core, at the cost of some performance for your best-made chips since you disable a core on them.
That could make sense for Apple; the M1 is already ~1 generation ahead of competitors, so axing a bit of performance in favor of higher yields doesn't lose you any customers, but does cut your costs.
Plus, they definitely do some binning already, as mentioned with the 7 vs 8 core GPUs.
Even Apple is susceptible to it. But Apple doesn't sell chips, they sell devices and they can eat the cost for some of these. For example if a chip has 2 bad cores instead of selling a 6 core version Apple is probably just scrapping it.