Macs aren't ''Walled Gardens'' we're not forced to use the App Store, we can download any applications and games off the internet while in the App Store we can only download Apple approved applications and games
That's not why they work so well, because using a Mac ≠ walled garden. I don't know how you conclude that it is. If you're referring to the Mac App Store, it's up to each user to decide if they want to use the store. I've never bought anything from the Mac App Store. Any software I've bought (most I've needed is freeware), I've bought directly from the developer.
It's not a walled garden. I rarely go into or look at the Mac App Store. While this might change in the future, for 10.8 and I'm sure for 10.9 as well this is not the way things work.