Yeah iOS is one thing as you can generally wait it out as Apple is pretty aggressive about upgrades there but on macOS I think this limitation has really killed it's viability, people just don't update their desktop OS.
Not to mention that Apple just orphaned a shitload of perfectly viable computers (first-gen Retina iMacs, for example).
I was also baffled to find that TestFlight can't be installed on pre-Monterey Macs. I mean... WTF? That makes no sense. Sure, we can pass DMGs around, but my company is new to Macs and standardizing our QA team on TestFlight on all devices would've been simple.
