Originally Posted by mcarling
If history is any indication, we can expect 10.7 to follow 10.6 by one to two years (or perhaps a bit more). That makes it likely that the newest 32-bit Macs will be approximately 4.5 to 5 years old when 10.7 will be introduced. The average age of a 32-bit Intel Mac will probably be over 5 years (perhaps even 6 years). Apple's general policy is to remove support for five year old hardware, as convenient opportunities arise to do so. It's difficult to imagine a more convenient opportunity to drop 32-bit CPU support, more inline with Apple's generally desired timing, than 10.7. Is it conceivable that Apple might drop support for 32-bit CPUs only with 10.8? It's conceivable, but the chances seem only a little bit more likely than a return to PowerPC.
The problem with dropping hardware support after less than about five years is that it reduces customer satisfaction. The problem with dropping hardware support after more than about five years is that it reduces sales.
I don't like making these kinds of predictions, because what is happening now with Apple's processors is not what happened before.
When Apple moved to an entirely different architecture going from 68xxxx to PPC, they dropped support because the technologies were so different and it was difficult to support features that were only found on the PPC, on the older 68xxxx. Same thing with PPC to Intel. Totally different architectures. As Intel moved away from more standard designs that weren't all that different in the features they supported from the G5's, supporting the older chips became a liability because of the increasing expense.
But this isn't so true with 32 bit x86 vs 64 bit x86. While it's true that newer chips support more sophisticated vector processors, memory etc, the basic ship architectures will continue to be the same.
Because of that, supporting 32 bit for one more generation of the OS is not out of the question. It now becomes a matter of marketing, sales numbers, and philosophy for Apple.
But much of the technical reasons won't be there.
By 10.8, it will be different for certain.