I get a big kick from anyone who criticizes a company for making software that has design elements similar to other products. I'll tell you what, design an OS from the ground up and include absolutely nothing from any other OS that has ever been available. Go ahead, claim IOS is new. Multi-desktop is linux and icons on a grid are on every Windows desktop. At least they both give you access to the file system (by the way, the OS you're making can't have a file system, that's been done.)
Every (good) developer draws inspiration from things that have been successful or that he/she thinks will benefit the design. If that means there's a layer of familiarity in the new devices I buy then that's an added bonus. Windows still has the PC market and linux PC distros are gaining on Mac. Having that many people in the world feel more comfortable with your OS because it somewhat reminds them of the ones they already use is not a bad thing.
P.S. When you're building this new OS for us, just remember, you can't use icons, widgets, applications, wallpapers, touch input, mouse input, keyboard input, sync, etc. That's all been done before and we wouldn't want any more copycat OSes out there. Well, is it ready yet?