Maybe a given number of years isn't what the yardstick should be, but rather whether the hardware can still be reasonably used.
For example, I have a 3rd gen Intel Xeon that runs circles around regular newish processors in brute processing force (think compiling and such). Yet, MS doesn't officially support it anymore with win11. I know you can circumvent the TPM requirement, which I do, so I'm still using it, but this just shows how arbitrary this limit is.
In Apple's case, at least they can say it's a different architecture and whatnot.
For example, I have a 3rd gen Intel Xeon that runs circles around regular newish processors in brute processing force (think compiling and such). Yet, MS doesn't officially support it anymore with win11. I know you can circumvent the TPM requirement, which I do, so I'm still using it, but this just shows how arbitrary this limit is.
In Apple's case, at least they can say it's a different architecture and whatnot.