They do control Play Services, however. That’s not open source and includes proprietary apps basically essential for an operating smart phone such as Google sign in, Maps, and of course the Play Store. Google used their market dominance in those fields to prevent third parties from launching or installing competitors to the Play Store by denying Play Services to those who didn’t comply; paying them off directly or brokering sweetheart deals. That’s appears like an obvious abuse of their market position.