But you have to navigate a circuitous route to find that notice.
I think tech pundit Andy Ihnatko might have nailed the reason for the incompatibility in today's Macworld column:
And! Beginning in November, all apps submitted to the Store must be sandboxed. Sandboxing (one of Lion’s star features) is a pain in the butt for developers but its practical benefits for users are crystal-clear: ideally, in a sandboxed world, no running process can interfere with any other running process, no matter how naughtily it’s behaving.It seems to work for me, though when the viewer misbehaves, it does so spectacularly. For example, it fights with the Safari Web browser. Running both can be dicey at times as the Official Viewer is such a resource hog.
Hopefully we'll see a compatible browser by November. I'd like to think that The Lab is proactively working on the sandboxing requirement. Probably not. I doubt the viewer would be available via the App Store. It would make far too much sense to expose one's product to such a huge audience. It might upset the current decline in population by having more folks install your product to try your service.