This is a smart corporate move by Apple to keep unit sales current. Whilst many of us with older machines might not be entirely happy with this we might have to end up shelling out the extra bucks for a new upgrade. Personally I'm not happy when a company uses its software sales to boost sales of newer hardware but it is and has been the trend in the technology arena.
My big issue is also lack of support for the older OS. How is it that 10.6.8 users cannot have access to the newest version of Safari. How about iCloud support, really Apple? It goes far beyond just an updated OS that Apple is doing this with. It's absurd really and disappointing on the other end.