The wall is the "standard" store. Pretty much like Apple does, because you can also jailbreak an Apple and this doesn't make their ecosystem any less of a walled garden.
They are trying to become a channel just like Ubuntu and like every man and his dog seems to be doing lately. At this point their interests and those of the users don't necessarily align 100% of the time. The same applies to Google, Apple, Ubuntu, and a bunch of others really. If you just want the best possible desktop environment and nothing more, I'm sorry but that's not their priority now and compromises will continue to happen in that regard.
You don't need to "hack" Android to install any app from any source you want. Same goes for Linux distros including Ubuntu. Package managers are not App-store type walled gardens.
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).
They are trying to become a channel just like Ubuntu and like every man and his dog seems to be doing lately. At this point their interests and those of the users don't necessarily align 100% of the time. The same applies to Google, Apple, Ubuntu, and a bunch of others really. If you just want the best possible desktop environment and nothing more, I'm sorry but that's not their priority now and compromises will continue to happen in that regard.