It's is unrealistic to expect them to provide new versions of software that work with older operating systems, but it's completely reasonable to request them to allow access to older versions of the software that already exist. Personally my primary studio computer is an x-serve, which apple discontinued support for after 10.7. besides that it's a sweet spot for me where I can still run older 32 bit plugins that I can't necessarily update because they wouldn't work on a newer OS, yet I can still run most 64 bit plugins. Professional hardware is designed to last for decades, and can continually be serviced, this is why it costs so much, it's designed to last. It's not ridiculous to expect the same from software. I'm about to find out how it will work for me, I just purchased a drumbrute impact and a microfreak and I really hope the software will work with 10.7. if not I do have a MacBook that is maxxed our at 10.13, but to expect me to buy a new computer just to run software to control older hardware is ridiculous and it's a major intentional pitfall of Macs. If I can't even manage to upgrade firmwares I guess I'll just eventually be going back to windows, but it could so easily be circumvented by offering older versions of the software that are OS locked like for instance my DAW, Cubase does. It's just the professional thing to do.
Sorry I'm not trying to come off ranting, there's just such a simple way to make things work for anyone on an older Mac who can't fork out 1+2 grand for a new one, especially when their old one works just fine.