You state:

"People complain about UIs not being intuitive, but no UI is intuitive; its simply learned behaviour."

I beg to differ here. When a 4 year old girl can pick up an iPad and within minutes be happily using it, there has to be a level of intuitiveness in the way the system is designed. In fact, most people that design interfaces, do so with human behaviour (a lot of which is intuitive) in mind. They count on this intuition to allow for fast adaptation.

So, yes, there will always be a level of learned behaviour, but intuitiveness is definitely a big factor.