When debating the openness of platforms, an example oft mentioned is consoles: Microsoft, Nintendo, and Sony each own their respective console market, taking a tithe from every transaction occurring on the device. Such an example has frequently been used to justify various of Apple's actions.
I don't buy it, though.
My xbox is just a toy, in essence. It's an entertainment device that I could discard with little loss. A general computing device, which is what I think both smartphones and tablets are, however, are not game consoles. They are not merely entertaining frills. This sort of "landholder" gatekeeper model cannot and will not fly.