On the hardware front, Apple go to the other extreme: there is no modular API for direct hardware interfaces. They own the full stack, from the external ports, all the way up to the UI, and, in the case of the dock connector on portable devices, even that is proprietary.
Their software delivery mechanisms are pretty locked down as well (almost completely so on iOS), but they keep hold of the developers by permitting the ability to "roll your own" when you really need to (hence the popularity amongst developers of systems like homebrew)