good enough and relatively free is the enemy of excellent and expensive.
ditto smartphones killing so many standalone devices, from music players to cameras and gps units and games consoles and and
Actually there is a bit of feedback going on:
* iPod Touch, the last remaining device under the portable media player brand iPod, is an iPhone sans the cellular modem. (If I recalled it right, one early model iPod Touch flat out used the iPhone logic board as-is without the 3G modem installed, and the connector footprint for the 3G modem is clearly visible.)
* Nintendo Switch, likely the first 9th generation game console, is based on the same Tegra chipset as used in some smartphones.
* A lot of consumer cameras now comes with Android for wireless connectivity and image enhancement applications - almost as if it is a smartphone with cellular modem removed and camera module beefed up.
* The TI Nspire series graphing calculators uses their OMAP processor, as used in some early Android devices.
etc.