I totally agree with you. You can't say this is a rip off... an OS is an OS. Google, or anybody else, would not have much choices when comes to build a new one. Window, apps, app store, etc. are fundamental to a mobile OS. Maybe Apple made the first one to be massively adopted and recognized, but they are not really inovators, they always took something that alreay existed (excepted first computer) and made it a more appealing product for the mass market. Take iPod, iPhone and the iPad for instance. Mp3 player existed before the iPod. They took the concept, built an appealing product from it and sold it to the mass market. Same thing for the iPhone, took the concept of a mobile phone, put it in their iPod OS. Again, same thing for the iPad. Tablets were there. They were unpopular due to a lot of reasons. Apple took the concept, improved it and sold a better product.
Give them credit for make awesome product out of existing ones, but quit saying they invented everything and everything else is a rip off.