Vista is 2 years older than Snow Leopard, and half a year older than Leopard.
I think these are data enough to conclude that Apple wants money: PC users to buy iPhones and Mac users to buy the last thing they produce. Even if they don't need it.
We are not pretending to do the new things with the old devices, think about it.
No technical reasons now. No processor change, no technology change... but functionality drop. Sad.