Apple's money comes from selling a cohesive experience. That, on iOS, that's been helped by a "walled garden" approach does not indicate that the same approach will make OS X better. Some people have been crying wolf since iOS 1.0 about the demise of the open Mac platform. They were wrong about Snow Leopard, they were wrong about Lion, and they're wrong about Mountain Lion. It's beginning to sound like a certain boy and a certain wolf.
It's clear that Apple is making OS X more and more and more like iOS. I think you're right the loud-mouth "DOOM" scare posts are a bit silly and I hope I'm not coming across that way. I just think that people are accepting this when they wouldn't have imagined OS X looking like it will soon with Mountain Lion a year or two.
Sigh, if you're going to downvote, please have the courtesy of telling me what was so inflammatory about my post. Especially if you're going to drive by downvote all of mine in a particular portion of the thread. I mean, good god, this post is simply a listing of observations and then an agreement with the parent that many people draw absurd conclusions.
Actually, nothing of the kind ever happened. Maybe some idiots did, but security experts have been nagging Apple to add signed apps all the time (Windows had them for ages), and people were also interested in a Mac App Store (not to mention developers, who saw it as another gold rush after the successful iPhone App Store).
Besides, from the very first OS X, say, 10.0.1 to 10.8, nothing has been taken away from user freedom. What exactly can't you do in 10.8 that you could in 10.0.1? They only ADDED stuff, i.e not you can also get stuff from the App Store, and in 10.8 you can also run secure, signed, apps.
Plus, why wouldn't OS X have a "walled garden"? Linux distros had one for ages, we call 'em "package repositories". Yeah, you can install stuff in other ways too in a Linux distro, but then again, so you can on OS X 10.8.