yeah, ok, this is a common critique of android in that apps aren't optimised for a tab. Its a bit wierd to use portrait on a 10.1 tab but if the app works i put up with it. This is one reason why the 7 inchers tend to do better than 10 inchers where landscape is the norm for everything. What is the norm for a 7 incher ? either orientation works, portrait being better.
Bear in mind that the ipad is a portrait device, for one hand readers to begin with. So there wasn't all that much work required to have apps both on iphone another portrait device and ipad to work.
Thing is once you get used to apps and the way they work, the reason to switch platforms becomes moot. It's a hassle. You get used to the way things are and it becomes the norm, you can get what you want, know how to use the app so unless there are some extenuating circumstances no reason to move elsewhere.
Apple has the head start here, and to managed to hold onto it an important bit of it so far.