Nah not really. Having a top-end iPhone or Samsung be a hardened device by default would mean world leaders would be protected on their personal devices. Also,

Nah not really. Having a top-end iPhone or Samsung be a hardened device by default would mean world leaders would be protected on their personal devices. Also, most anyone who talks to a world leader would get that same protection. On the other hand "run of the mill" phones that you can hand to a teenager (or use as a backup phone) don't need ultra-security and the cost that comes with it. Really low end devices would probably be secure by simple virtue of not having enough features to enable hacking.