c) is nonsense. There are no downsides to a temporary boost in Nvidia's profits, even if it means profits eventually falling back to normal levels when ETH drops in value. Also, LHR (gaming) GPUs and CMP (mining) GPUs share the exact same supply chain and components. When/if crypto demand suddenly drops, Nvidia will still have to deal with the oversupply of components. Having segmented the market between LHR and CMP GPUs does not in any way make it easier for Nvidia to forecast overall production capacity.
It is a real risk when gamers (the every day bread and butter) or ML model folks (emerging bread and butter) markets will stop using them because they can’t get reliable supply. Both of those groups do quite a lot of driver validation, workload tuning, and other platform specific stuff. If another competitor gets those markets, that will hurt for a long time.
According to Tom's hardware analysis the CMP gpus are leftover Turing architecture that would otherwise have gone to the now less desirable GTX 1660 Ti, or 2080 Ti.
And when they are finally using the new Ampere silicon, it's likely those chips that did not pass QA for being made into a RTX 3080.
So they are getting rid of overstock/dead stock already.
