I think it's very interesting. Also very hard to achieve, different hardware needs different drivers, might have different pin configurations, different number of pins... making a universal base PCB and OS is very complicated. The OS is the easiest part. Note how occasionally x86 CPUs will change to a new socket type, requiring you to replace the mobo, and sometimes even the RAM type changes so you have to replace that too along with the mobo. It's a similar thing for mobile devices.
But it would definitely be awesome if achieved.