* The Xcode example isn't a reality. I can see my Mac application outside of the appstore without giving Apple a penny. I can sell my corporate iPhone / iPad application without giving Apple a penny (corporates can obtain management tools that allow them to load applications without using the appstore). It's true for a subset - consumer iOS apps.
* I've had Xcode prior to it's free availability in the appstore and have never had an ADC account - it was on the CDs with my MacBook.
On the first point, I was specifically referring to iOS apps, and you cannot "sell my corporate iPhone/iPad application" in the way you describe. Side-loading is only available to businesses with more than 500 employees, and as far as I understand, is only for internally developed applications.
Fair enough on the second, but it's tangential to the point. Apple constrains the distribution channels of iOS apps built using Xcode. This specific case is analogous to the iBooks Author tool restrictions.