AMD's use of chiplets matters here. There is overhead, but they also not only get higher yields, but also have many more chips that can hit their highest target clockspeed meaning they can ship far more high-end chips.
This is the same reason why they were so successful with EPYC. It's easier to find eight small 8-core chips with high clocks/low-power than to find one 56-core chip with that same high-clock/low-power set which is why Intel sold so many cut-down chips while AMD just sold their small amount of defective chips as 6 and 12-core consumer chips.
Nvidia will have a harder time shipping defective because everyone wants the best chips with the best performance/watt to save money and do things fast. Outside of that, there's not a huge market for defective 800mm2 chips and the massive GPU the come on. AMD can sell their defective units a couple chiplets at a time to non-AI customers in laptops and workstation cards.
It's transparent, but it has a performance cost. There will be low-level ways to improve locality for certain libraries, but it's nearly impossible for common users to claw that performance loss back.
I ran 120k of the rx470-rx580 series and another 30k of the PS5 APU. All of them were run at the most efficient and tuned settings possible. Every single chip was a snowflake.
We're not just talking defective, we are talking about a silicon lottery on performance and it varies between every single one.
If the backlog gets too big, as a consumer you might get compelled to just abandon it and switch to the "available" alternative even if it's sightly inferior.
Suddenly potentially having a lot less backlog might screw up Nvidia faster that it "helps" AMD too.
If AMD sells say $3 billion USD into that market, is that a big net positive for them?