Earlier quoted context omitted.
Because app stores are acting as platforms as well as used to restrict third parties and improve first party products. Does Fortnite even have a platform for developing cosmetics and selling them? If not, then this argument misses the mark. Consoles do provide salient examples though.
Why isn't Epic forced to make it a platform? They have a large captive audience with money and I want a cut of it. Opening it up to everyone will drive competition to the digital skin market, and as we all know from this thread, that's a good thing. Why does Epic get to monopolize their game's monetization?
The answer to this question is quite obviously that the smart phone market is much much larger, and has a much higher impact on society, than an in game cosmetics market.
This is what courts care about. They care about real life consumer impact.
And anyone who is not stupid, or intentionally trying to mislead people, can understand than the smart phone market matters a whole lot more, than an singular in game cosmetics market, which means that preventing monopolization in the phone market is way more important.