In February 2017, I directed my daughter to this 2012 MacBook Pro, not only because it was the cheapest MBP available from the Apple Refurbished Store, and with a great feature set to boot, but also because I expected that since it was still being manufactured after every 2013 and 2014 MBP had already been dropped from the catalog it would be supported software-wise for a good few upgrades.

Unfortunately, though, while it is able to run Catalina, Big Sur is supported only for 2013 and later MBPs.

I think that not supporting a machine that was still being manufactured for between 1 1/2 and 3 years after some supported machines were discontinued is pretty shabby treatment by Apple!

(This may cast a new light on a discussion I recently had with joemike about Time Capsules, Base Stations, and Airport Utility in which I opined that Apple would surely maintain AU as long as the hardware that depended on it was still supported. )

It is not when a Mac was manufactured that counts, it is when the technology was designed.

I understand that, but it just seems disingenuous of Apple not to have contrived to make the machine Big Sur compatible.

I wonder how far out of the question it actually is?

Without access to Apple's hardware and software engineering teams and complete design details, there is no way to judge. I don't even have an idea why your daughter's MacBook Air won't run Big Sur. But it occurs to me, while the MacBook Air has long been Apple's entry-level price-leader, it has never been a technology leader and often generally re-used prior generation technology from its up-line siblings. Which could mean it actually goes back a generation further than the production dates would imply.

You've misread. It's a 13" Mid 2012 MacBook PRO.

My apologies, I somehow got the MacBook Air firmly implanted in my thinking. I even went back and compared MacBook Air and MacBook Pro releases. 🤦🏻‍♂️

In that case, all I can speculate is the difference is somewhere deep in the hardware, perhaps in one or more of the support chips. In all probability something, or things, that crossed over from the iPhone/iPad to the Mac. Wasn't it around 2013 when iOS and MacOS development began to be more closely synchronized?

2013 MBPs are the earliest ones that are compatible with Big Sur.

I guess my daughter's 2012 falls short of the hardware requirements, but having perpetuated the machine, Apple isn't doing the right thing by what I'm certain is many owners.