in the context of news of android devices forced in EU not allowing bootloader unlock, we need phone manufactures that still allow this and better yet if they already ship with GOS, in fact GOS has posted about this possibility, another possibility if android gets less open source, are phones running linux.
Discussion
If you use Bluetooth mesh you would not even need a traditional phone. Wouldn't need Graphene or big phone manufacturers skip Android. You would need a lot of adoption. Phone carriers will be a thing of the past, cell towers as well. Rabbit R1 (sucks right now) and similar devices will be the future.