I think you missed the point. The article is highlighting the increasing inevitability that OS X will become a closed system where you will only be able to install apps and add ons through the Mac App Store.
It may come to pass that a version of Mac OS X will ship with an option to only allow apps from the App Store. It would be a great thing to enable on less-technical-people's computers. However, making it compulsory would chase away the very users their platform depends on for success.