If this surprises you, I've got some bad news for you. Everyone does binning. Go buy 1000 5% resistors and test them. Instead of a normal distribution of tolerances, you'll find that there's an interesting trough around -2% to +2%. That's because all of the resistors are made using the same process and the lower tolerance ones are binned and sold at a higher price.

Same goes for silicon. The dies are largely the same. Only later in the process, they get binned to a lower spec cpu by selectively disabling features. Generally, this is because the chip doesn't meet some spec, but there are cases where this is simple done to meet demand.