Samsung 3nm had a yield rate well below 20% back in early 2022, and that's not unheard of while still in the development phase. To be economically viable the yield rates have to be around 80%, so mature nodes can be expected to be in that ballpark.
But the performance binning is a direct result of careful design that goes out of its way to ensure that a subset of failures can still lead to a workable/binnable products.
It's still a failure to produce a part that matches the full design.
