Because those are commodity processors nonetheless. The distinction relevant for a research paper is between mainstream processors you can just buy vs. custom made ones, not about market penetration.
I still think "commodity" is not the correct word even in that context. Mass-market, or commercially available might be better. How can it be a commodity when there is only one manufacturer?
Just going off wikipedia (also other sources support the definition):
> In economics, a commodity is an economic good or service that has full or substantial fungibility: that is, the market treats instances of the good as equivalent or nearly so with no regard to who produced them.
Basically it's a common good, that is sold and purchased, with no other modifications required for this use-case. This commodity is currently low in supply, but is still a commodity.
It’s missing the fungibility where it is produced by multiple suppliers and can be treated equivalently by the end buyer. Large grade A eggs are a commodity as it doesn’t matter which farm produced them. A specific set of processors from Intel are not a commodity since there are no fungible equivalents. Widely available would probably be a better description in this case.
I would argue processors are never commodities anymore (maybe back in the 486 days it was closer). You can't swap an intel for an amd processor into the same motherboard ever today. They don't have the same performance characteristics from one to another. You could have 2 "3.5Ghz 4-core processors" that have wildly different real-world performance. IMO this is the opposite of "fungible"
I think hard drives, memory, power supplies are much closer to being fungible.