[iSnow]

>It's up to the user to decide whether a machine is usable for their needs or not, not Apple.

Well yes, but it is also a business decision. Further supporting an old machine with a changing toolchain means additional costs for development, testing and troubleshooting. Those are costs that Apple has to bear.

I won't contest your point that 3-4 years is too early, just saying that there's more to supporting old hardware than just including the same drivers as in the last release.

[ivraatiems]

You're absolutely right, but at the same time, if something WILL work but may not work optimally (or may not be supported for business reasons), I think it's more appropriate to say "hey, this is not recommended and if you do it you're on your own" than "you may not do this, no matter how well you know the risks." Apple chooses the latter path.