It's a "walled garden" instead of just a prison camp, because it's not completely forceful but it's enough deterrent to keep control over the average user which is what moves the economy.
You can, theoretically, find apps outside of the "official" channels and install them. This is not what usually happens and this is not what's encouraged. The success and visibility of apps outside of these channels will always be limited at best, so de-facto they control what people run for the most part, and that's more than enough.
If you mean something different by "walled garden" then maybe we're discussing over semantics. Apple does go a step further though, if you mean that Apple's is the "only" walled garden.
On Debian, the standard packaging system is APT, and it is more work to install software from alternative sources than it is to run `apt-get install`. Is Debian a walled garden? Why or why not?
Please answer my question. If package management shares the characteristics of a "store" in that it is the "blessed" and easiest method of obtaining software, what makes it not a walled garden while app stores are?
Debian keeps a minimum imposition policy on their package management. Often they will do the packaging for you even.
In a walled garden, apps are taylored exclusively and you have to do it. They also impose conditions going further than licence and stability. Eventually they ask for a cut of anything you sell over there (which is something Debian hasn't ever done and won't do).
You can, theoretically, find apps outside of the "official" channels and install them. This is not what usually happens and this is not what's encouraged. The success and visibility of apps outside of these channels will always be limited at best, so de-facto they control what people run for the most part, and that's more than enough.
If you mean something different by "walled garden" then maybe we're discussing over semantics. Apple does go a step further though, if you mean that Apple's is the "only" walled garden.