Android has a Linux kernel and uses it's stack. As a person in the field I can tell you that the IoT is not just smart lights. There are starting to appear smart sensors or even car infotainments which are Linux inside. Sure, car infotainments are not controlling the engine power or throttle but it is for sure requesting engine start up or displaying the glass cockpit in modern cars. Otherwise how do you think you can turn on the car with the new fancy app?

From what I see we are going back from general computers running an old version of windows xp or red hat into special purpose Linux system on a module devices.