Apple's "post-PC," "new media" iDevices are selling quite nicely, thank you. Millions of people have become enthusiastic, loyal, even evangelistic customers without ever clicking a mouse on an Apple desktop or laptop computer. Given that Apple's profit from a laptop or desktop computer is several times what it is for an iDevice, it's almost imperative for them to find ways to make the Mac desktop/laptop user experience support the traits that have been most successful on iDevices. This includes, especially, the App Store.
Fans of the App Store, either on the iDevices or the Mac, point to the fact that you can have several different devices (iPad/iPhone, iMac/MacBook) using the same Apple ID, and thus can install "content" that you "purchase" on several devices; all you need to do is register them under the same ID.
But the Mac, historically, has had a rather different model. You would (and still can, fortunately; at least for now) either purchase a disk with software on it, or download a "disk image;" a file which appeared to Mac OS to be a disk. As soon as you did that, a window would open with the program icon in it and an icon for your Applications folder, and you'd drag the icon over onto the folder. The software would be copied to your hard disk, and you'd be able to then run it like any other program. Want to uninstall the program? Drag its icon to the trash.
Another benefit of that latter model is that you have actual media — either physical or virtual — which you can use to reinstall the program on your computer or, license permitting, on other computers you personally or corporately own. You're very aware during the "normal" installation process that you're working with some sort of artefact which contains the program you're installing. That artefact either is or tries reasonably successful to simulate a physical object.
We've built up certain expectations about physical objects. They exist; though they can be destroyed, they don't generally disappear without direct action by you or another person. With very few exceptions, they can be used more than once. These and other expected traits give the object some value — economic, sentimental or otherwise.
The App Store for the Mac does away with the artefact; it replaces it with an abstraction that's not "real" in any sense you can point to afterwards. To a degree that some find disturbing, it turns the product with which you previously dealt into a service. That service can become unavailable for any number of reasons, not all of which are necessarily a result of your actions or intent.
Put another way, it turns the old "software as a product" notion, and in particular the notion of free software, on their heads. Most free software licenses (try to) make clear that the user is In Charge of his or her own system, including use of the software being licensed. The copyright holder retains certain rights, but yields the remainder to the user under conditions designed to make sure that the software remains "free" in the sense that it was originally licensed. The user may examine the software, redistribute it as he got it, (under most FSF-approved licenses) can create modified or derivative works so long as they are licensed compatibly to the original, and so on. Above all else, the user has the unquestioned right to make as many backup copies of the software as desired in case the original installation becomes unavailable (hard disk crash, extreme weather event, etc.) The user has rights, and has the means to safeguard those rights by virtue of the fact that he has a physical copy of the software in its original, usable form.
The App Store says "Mr User, you don't have to worry your pretty little head with any of that. You just point-and-click your way through the store, and when you check out, the software will be installed automatically on your system." That's great — so far as it goes. But there's no option, at least none that I have yet found, to retain a copy of the disk-image file(s) for the software you just licensed. If your drive goes south for the winter and doesn't come back, you "just" replace the drive, reinstall Mac OS X and install all your apps from the App Store.
That's fine for small programs, especially if you have a high-speed Internet connection using a properly managed ISP. But, unlike the App Store for iDevices, several programs licensed through the App Store for the Mac are in the hundreds-of-megabytes-to-gigabytes range. Try downloading Xcode 4 on a 128K ISDN line. And iLife. And iWork. And... you see the problem. Wouldn't it be much better if you at least had the option to manage all that locally, yourself, the way it's traditionally been for the Mac? And that doesn't even take into account Apple's well-documented "control-freakery," where software available one day — or even already installed on your system — may not be available the next. Even if we give Apple the benefit of all doubt, ascribing to them motives as pure as the driven snow, there's still a real problem here.
The iTunes Music Store has now moved away from "protected" DRM-encumbered music, because customers made it clear that they wouldn't stand for the inconvenience and loss of control over product that they had paid for. I can back up my iTunes library however I wish, and be reasonably confident that should anything happen to my Mac, I'll be able to restore the library on my new replacement Mac without downloading it all again from the ITMS.
Why can't I have that same confidence with the software products I license through the App Store? Apple aren't the only ones who think they should have a fair amount of control over "their" "stuff."