Quite a factual analysis dear Bob. I would like to add that the real strength of smart phones lies in the following features:
1. Strength of OS to make it impenetrable enough to provide peace of mind to user from safety against malware and
2. Strength of Microprocessor to enable App developers to innovate and make available functions not even imagined so far.
Who knows tomorrow some smart phone may come equipped with Apps providing infrared night vision or photography or remote measurement of temperature of things infrared sensing … and what not.

My age is 81 and I belong to the generation that managed big business without even calculator. Those of my generation had private secretaries capable of calling and asking somewhat like, “Sir, now that you will be returning from USA via Pacific rather than Atlantic, would you like break at Honolulu – Hawaai for a couple of days for your anniversary and should I arrange for your wife to be there for the anniversary there”? I look forward to a day when my smartphone is capable of such a function.

Therefore, for the present sky is still the limit for all smart phones.