Ipads can't get google play either... they are different operating systems and have different app stores... ipads run iOS and get the Apple App store, most other devices run Android and get Google Play, Windows tablets run Windows (RT in your case) and run Windows app store.
Windows app store is the poor relation to the other two for sure, but I remember when I first got an android phone an iphone user was taking the mick out of me for using android and how "small and rubbish" the Android Market (as google play was called then) was.