>the parts aren't "junk"
You don't know for sure. How likely is it that the manufacturer of the knock-off part performed full characterization of their chip to ensure they are within spec limits of the original manufacturer? What if the chip starts sending wrong bits when the temperature gets a bit high or voltage supply fluctuates somewhat? Don't you think getting disabled by driver might even be a less disastrous failure mode in this case?
No matter how you slice it, this is lunacy. FTDI was extremely short sighted here and any competent engineer or product manager will see this as a sign to be weary of incorporating FTDI into future designs. You don't want your component manufacturers playing shady stuff like this. Supply chain management is complicated enough without having to worry about devices getting bricked weeks, months, or years after you've done the engineering work.