In reverse order...
"Apple are making it more and more clear that the Mac doesn't have a long-term future."
Really?!?!? Where's the evidence for that? I've not seen anything even remotely hinting that the Mac has no life**. Making changes so the desktop is more consistent with i devices makes sense.
I'm guessing that the increase in sales of mac's is due to ordinary people now choosing them over a Win PC - more than likely after a positive experience with an iOS device.
"I wouldn't count on that being the case for long"
So you really think it's likely that the Mac line is going to be nobbled in future? Then how are the iOS/OS X app(lications) going to be written that keeps the consumers coming back for more?
Is Apple suddenly going to allow apps to be developed on a competitor's OS?!?!??!
** It's a long read, but Gruber's take on OS X makes sense to me...
"It seems important to Apple that the Mac not be perceived as an afterthought compared to the iPad, and, perhaps more importantly, that Apple not be perceived as itself considering or treating the Mac as an afterthought."