iPhone store is DRM. It helps the customer in a way by preventing apps from breaking the phone. I don't like it personally but I have a higher knowledge level of technology than most people.
DRM is useful mostly to people who can't figure out anything in a technology product. They are more likely to break their products without it than with it. The big thing though is I wished companies offered an option to those who are willing to risk it all vs fighting them.
You are confusing DRM for the locking down of a product or platform. Apple locks down iOS for the benefit of the user (most of the time), but adds DRM to apps to prevent unauthorized code from being executed on the device and to prevent apps from being pirated (which Installous has proved futile).
DRM is useful mostly to people who can't figure out anything in a technology product. They are more likely to break their products without it than with it. The big thing though is I wished companies offered an option to those who are willing to risk it all vs fighting them.