That is specifically a design flaw in the AOSP. Right now manufacturers have to integrate their custom device drivers into every new OS build, leading to long delays and fragmentation. The device drivers should be separate, and the OS should expose a stable API and integration points. That way OS upgrades could be pushed out without breaking everything, just like with desktop OSs.
That's not Google's policy, it's Linux. What you suggest would mean abandoning Linux as a kernel. I'd be all for it - the industry needs some more open source kernel competition.
Linux is a bad choice for a half-open environment. Either it's totally open (like most Linux distros) or everything is done by the manufacturer (like routers). But not this garbage with closed source drivers that will prevent you from recompiling eventually somewhere in the future.
