It would be a lie though. Since it really would be a Turing complete phone, with lots of programs on it. That was true even of the old Symbian phones, and items from 3-6 go well beyond what they did.
Nonetheless, I think there is benefit to be gained by trading flexibility for reliability. One business difficulty/opportunity is how do you pick out services like Uber, AirBVnB etc. I suspect the solution is profitable, but user hostile: lock them into a vendor when they buy their phone.
In a way, it's a feature, not a bug. The security of mobile devices is created by the very same thing that limits their usefulness - by OS being vendor-controlled, fully sandboxed and locked down, so that users (via programs acting on their behalf) can't break it. I'm not sure if it is even possible to have a secure system that allows you to do anything interesting on it.
7. Games
I loathe using my phone for most things. Any opportunity I get it is hotspot + laptop.
The only upside is it's easy to track you with these devices by those who care about you the most: big $$ and big brother.
After trying a lot of apps I have found that a smart phone has only a few functions:
1. Talking and texting.
2. Taking pictures and video.
3. Maps and directions.
4. Music, movies, ebooks.
5. Brief interactions with services like Uber, Lyft, AirBnB, Los Angeles metro, etc.
6. Casual web browsing. (I want a bigger screen and a keyboard for anything in depth.)
7. edit: Casual gaming.
Looking at how most other people use phones I don't think I am alone.
These devices are limited and I don't think it took us long to exhaust their potential. There just isn't much else a phone can do well (and that locked down vendor fiefdoms will allow).
The PC era on the other hand gave us a long, wide, and deep trench of innovation that is still not exhausted. PCs are more open, more extensible, and have a much wider IO path to the human in the chair. The breadth of what a PC can do is incredible.
(The main problem with PCs is antiquated, insecure, bloated operating systems. Fix that and I think you'd see even more innovation.)
Of course I have been a mobile skeptic since the iPhone. I just saw the next incarnation of the feature phone. Since it was still locked down by carriers and vendors and since its bandwidth to the user is poor I knew it would not deliver lasting innovation.