I think their main reason is that Apple is a hardware company. They think of new features, build hardware for them, and then tweak their software (OS and applications) to aggressively use that new hardware.
Supporting older hardware is extra work that doesn’t bring in extra money. Also, oftentimes, it isn’t possible to backport features in a performant way (a lot of the ML stuff would only crawl on 10 year old hardware, features such as Handoff and PowerNap require hardware features). End result would be a 20 year old machine that runs the OS, but doesn’t work with modern software.
That wouldn’t make customers happy, and would dilute the brand of their OS releases.
I have a macbook pro late 2013 with a retina display, i7 cpu, 16gb ram and 512gb ssd that doesn’t get monterrey. I am not very happy about it, it’s a waste
Supporting older hardware is extra work that doesn’t bring in extra money. Also, oftentimes, it isn’t possible to backport features in a performant way (a lot of the ML stuff would only crawl on 10 year old hardware, features such as Handoff and PowerNap require hardware features). End result would be a 20 year old machine that runs the OS, but doesn’t work with modern software.
That wouldn’t make customers happy, and would dilute the brand of their OS releases.