Recent Intel Macs are gonna be supported by Apple for at least a few years. There's no way they're going to get two years down the road and say "tough luck, people who bought a computer from us in 2021!"
I agree, except for this part.
People who own iMacs from the mid teens (~2015-2017) are now finding that their firmware will not upgrade if they purchased the SSD option Apple charged so much for at the time. This problem emerged in early 2020 with one of the upgrades that changed the system firmware. So, it wasn't two years down the road then - it was three.
Apple has variously told owners when they get an eficheck alert that the firmware they are running is the latest, that the owner must be doing something wrong, and a whole assortment of what really amounts to lies and obfuscation.
There's a thread discussing this here:
https://forums.macrumors.com/thread...te-2015-efi-firmware-update-failures.2228324/
Something has happened at Apple in the past half decade. They are breaking software functions faster than they are fixing them. (Why break something that is working??) The company seems wholly uninterested in fixing these bugs or fixing their process. They seem to be taking security issues seriously, but to what degree nobody really knows.
Go visit
https://macperformanceguide.com for a whole stream of software failures that keep getting worse. Or, look here:
https://www.zdnet.com/article/apple-seems-to-have-forgotten-about-the-whole-it-just-works-thing/ "It just (doesn't) work" seems to be the company slogan now. You can devote entire days reading about this through simple Google searches. Ask people who lost zillions of emails that had been handled by the Apple mail app when they updated.
Yeah, this is whining on my part to a degree. But, I do want people to know what they are getting into. Apple hardware is generally superior and lasts a long time. (I have a ~2006 white iMac with a Core 2 Duo processor that I updated with an SSD. It still runs great with Snow Leopard and Windows 7 in Boot Camp. Really great.) It's the software that tends to make things a mess, and Apple seems to have lost whatever thing they had that brought the great results of Snow Leopard. The company emphasis now seems to not be on getting things right, but on getting cosmetic things new on a yearly schedule. That may or may not be helpful to you as a user.