8-10 years is what the Consumer Rights watchdog expects for devices in the price range of a MacBook in my nation to continue to provide hardware support, so I w

8-10 years is what the Consumer Rights watchdog expects for devices in the price range of a MacBook in my nation to continue to provide hardware support, so I would say that seems like a reasonable amount of time for there to continue to be software support. MacBooks aren't cheap. For the average person they are a significant expense. So the lifetime of support should reflect that.