This is the 5-4 supreme court decision: 17-204_bq7d (pdf) that gives green light to an antitrust case based on the damage to consumers due to abuse of monopolisitic power by Apple.
It is difficult to argue that prices (including 30% to Apple) would not have been lower if this 30% would not be imposed thanks to its artificial closure of devices. (unnecessary, I would add, as you can install/remove any app you want to/from other Apple products, sourcing those apps directly from suppliers).
I recall when, 1,5 yrs ago, some notable persons in Italy argued in a written memo requested by top politicians that #deviceneutrality (wikipedia) was not an issue.
Then I forecasted, #deviceneutrality would happen first in th US, by an Antitrust decision.
We might well have it coming…
p.s. I am long calling for portability+interconnection+interoperability obligations to be imposed to OTTs with SMP. I have some doubts Europe will legislate in that direction; I think that eventually the US will act, eventually via an antitrust case, when they will fear chinese OTTs and hence they will (re)discover themselves as procompetitive regulation fans.