I agree with you that Apple sales are not to be questioned. But if you look at iPad sales individually , you'll see that it hit a plateau where its not increasing anymore and actually started falling. That's mainly because people started realizing how the iPad doesn't deliver anything new. Its an iPhone on steroids.
I dont think WP users mock the visual homogeneity as much as the internal differences. An iPad brings nothing more to an iPhone other than a larger screen. Windows 10 will bring PC level functionality to phones...well as far as we know it will.
Apple is far from homogeneous. Microsoft is working on a truly homogeneous OS. This OS is coming from the top down instead of the bottom up. Imagine a phone you can connect to a docking station (like a Surface Pro tablet) and get a full fledged computer. That is the end goal. Mobile CPU's are getting fairly close to handling that heavy of an OS. Well at least to atom cpu performance not gaming performance. Microsoft will be ready for that day. Instead of being years behind like they were with Windows Phone 7, they will be the innovators. Apple in the meantime will try to convince everyone that their workaround version that only syncs notifications and phone messages between phone and computer is all you need in life.
I can't wait for the time when I only need small docking stations and screens around my house that I can connect my phone to. Better yet, I can just connect my phone via bluetooth and my house is a giant PC with a home phone system integrated. Not a single laptop or desktop anywhere. Isn't that what Bill Gates house is like now?