The line might be able to be drawn between devices which have support, or intend to have support and will accept applications/plans, for 3rd party software and

The line might be able to be drawn between devices which have support, or intend to have support and will accept applications/plans, for 3rd party software and those who don’t. By accepting third party software, the third party now becomes dependent upon (and in this case: a customer to) Apple. In these situations, the device producer has knowledge about and leverage over on-device application competitors which other third parties would not.