And honestly, people complain about Microsoft not porting DirectX 10 to Windows XP. Microsoft have given (they had to) technical reasons for why that would be extremely difficult.
I doubt very much there would be anything too difficult about porting Core Animation to Tiger - what has changed that would affect it?? It could just be a simple recompile.
Unless there are technical reasons that it would be difficult to port Core Animation to Tiger, what Apple's doing is not less bad than what MS is doing with DX10. But Apple, like MS, have to do shit like this - they have to pay their programmers, and keep some money for their $1000 cigars.
(free software ftmfw)