Counterfeit prevention is not just some sort of 'this part is real but this other part is not', it is about system integrity. How do we in the world of technology prove integrity? With cryptography. It's the only thing we have.
Same with your anti-theft proposition: if anyone can do whatever they want with my device, then nobody is deterred from stealing it.
Same with security in the sense of interdiction, injection or extraction.
None of these items, not a single one, can work without public-key cryptography. And until you (or someone else) comes up with a system where that does work, none of this matters and the status-quo remains as-is.
And yes, all of this is better for the consumer, even if the 10 people who want to fiddle with their phone can't do that without losing features. If you want a hackable device, get something else.
I, for one, do not want just a device where practically anyone can manipulate it, even if that means I cannot manipulate myself it either.
If you cannot come up with an argument that preserves integrity you don't really have a point.