To me, this is the crux of modern antitrust, and the EU absolutely got it correct at a high level.
In simplest form -- doing certain things as an almost-monopoly and/or extremely large business should be illegal, while doing them as a smaller company should not be.
The scale of global businesses, in low-competition industries, allows them to engineer moats that are deeply injurious to fair competition, to their own profit and the detriment of everyone else.
> you buy it knowing that.
I think it's debatable whether the average iPhone customer buys it, knowing it allows Apple to heavily tax all AppStore developers.