Earlier quoted context omitted.
I think I have a better analogy: Apple operates a market with a significant portion of economic activity in several industries / verticals, yet it sets its own rules and even is party to transactions. That's basically the definition of a black market. Black markets are useful in some circumstances, but when they grow too big they have to be regulated and taxed. A lot. Good for Epic.
You have changed the definition of "black markets" to something else. A black market requires illegality. You are conflating "rules" of contracts and "rules" of law. I agree that Apple "even is party to transactions". I think that's the common problem with Google (eg. Froogle / Google Shopping), Amazon (eg. Amazon Basics), and Apple (apps that compete and undercut 3rd party apps or which don't have to adhere to the s…
So I guess my point was this: past a certain size / power concentration a market/platform has to have regulations that are answerable to a democratic/political authority, not to a private party. That's regulation, isn't?
"Grey market" is taken, so how about "brown market"? :)