No they get the billions from their intellectual property. There's a bunch of pro-user, pro-Apple, and pro-developer reasons why they are the single source for

No they get the billions from their intellectual property. There's a bunch of pro-user, pro-Apple, and pro-developer reasons why they are the single source for apps and payment processing, but that's not the source of the billions, as I just explained. There's a bunch of reasons why it'd be a PITA for everyone involved if they were forced to do this, but no matter what happens the revenue sharing is never going to go away as long as Apple wants to keep that business model. All the frictional costs (more lawyers and accountants) to verify they collect the right royalties is exactly why courts are ultimately going to side with Apple, because the current system is the ideal one for all parties.