When two entities control essentially the whole "market" for mobile OSes and associated app stores, and use their position to force their app stores on everyone, you no longer have a market. If we just forcibly split Google and Apple into smaller companies with separate app stores then maybe we could see what markets would do.
But the problem is that when everyone has gravitated to the two biggest app stores, there's no scope for market competition. The point is not just to have third-party app stores, it's to not have huge app stores that capture the whole user base.
"There is no market effect"? Why do the market effects disappear if some of the players don't play completely according to the desires of other players? Why couldn't it be that the optimum includes some amount of fee dodging?
You didn't answer my question. Why can't the optimum include some fee dodging? I agree that the app stores provide value to the developers, but it's also true that apps provide value to Google and Apple. If no one developed any apps, no one would use iOS or Android. Therefore it's possible that Google and Apple benefit more from an app that dodges fees but brings in users than from neither having the app nor those users.
They created a market and they are charging to be on the market. If you're saying "I want to be on the market but by my own rules" that's not a free market effect, it's breaking a contract.
If you say "fine, I'll go on another app store" then that is a free market in action - but good luck getting anyone to download your game.
But it isn't what is happening if they are staying on the platform's marketplaces and also bypassing payments. There is no "market" effect there.
Not saying I agree with the 30%, but third party app stores exist. That is the market avenue (and no one uses them).