How is hardware variability not a design decision? They limited the choices to improve the design. Windows never did and thus we have a boatload of APIs and driver issues and configuration options... just look at the sound cards, every company comes out with something different for setting up positional audio and adjusting your audio style and who knows what else. It's a design disaster. Giving third parties the right to do the same would result is the exact same mess. Oh well the specs called for this, but we added extra features to be more competitive. So users could REALLY take advantage of it we'd need a new config panel branded in our unique style and OMG we're back to MS.
Microsoft breaking up is a stupid idea on the face of it. If the fiefdoms are bad, how does making each department into a separate company make it any better? Who at MS is in charge of overall design? No one. There's your real problem. The biggest concern I have about Apple now is they've lost their head designer and no one has really stepped in to replace him. I worry the design teams will argue, fracture, and turn into MS.