Which may actually be the plan, as the EGS isn't the only revenue feather in their cap. If they're fine taking that hit because they get game devs twice (selling them distribution and selling them an engine their game is written in), more power to them.
In theory, one can model Apple the same way (i.e. the App Store is a distribution channel to encourage people to buy Apple hardware so they can use the channel), but it sounds like maybe Apple found a great rent opportunity and is reluctant to let it go. Time for someone to remind them they're a hardware company that writes software as an excuse for people to buy their hardware. ;)
That's not the same at all, there's no devices that solely run the EGS, there's nothing stopping any game studio from taking their game to Steam, Origin, GOG, or even making their own.