I see that kind of stuff said from time to time. But I don't quite understand. How is it growing?
And people talk about it (App Store) as if it's terribly evil of Apple but it's okay when it gets done on say a Xbox.
As to the XCode-is-required claim, that's been false for a very long time - their GCC is open source, and has been for years. It has only recently become easy though, I'll grant that.
Apple clearly sees iOS and its locked-down environment as the future and Mac OS X as the past. Given that, we can conclude that the overall openness of Apple's offerings will decrease as they focus their efforts on iOS.
Xcode is for-pay now, while it was free earlier.
Apple keeps breaking SIMBL.
Debuggers now need to be signed by Apple or self-signed; either way, it's a pain.
QuickTime X is no longer extensible via plugins.
It's back to being free if you have installed Lion.
>> Apple keeps breaking SIMBL.
SIMBL is a non-standard 3rd party framework. It would be more correct to say that SIMBL isn't keeping up with OS X development.
Citation needed? Or are you pulling that from OSX getting a dose of iOS UI? The existence of the app store is merely a sign that they make money from the iOS one, and wish to make more money.
SIMBL is a hack used to load hacks (a fantastically useful one, don't get me wrong there). Its very nature is fragile, and Apple has zero responsibility to make sure it continues to work.
For OS X 10.7.2, you can grab the source at http://opensource.apple.com/source/xnu/xnu-1699.24.8/.
The "README" at http://opensource.apple.com/source/xnu/xnu-1699.24.8/README has instructions on building and installing the kernel. Admittedly, while I have never actually done this, I've seen lots of instructions floating around for doing this "correctly".