The blogs have been filled for three years now with the constant wailing of the technorati complaining bitterly about the iPhone’s, now the iPad’s, closed system.
It’s nothing new.
The Mac now connects to everything, but the first Mac did not. It was designed to always have a fixed amount of memory—128k—with no way of ever expanding it. The core of the OS was in ROM, not RAM. It was Steve’s vision that if you made every single computer with the same exact OS and the same amount of memory, developers would always have a fixed platform for which to develop, making their jobs easier.
The difference is the App Store.