The problem is if mac sales continue to decline. Mac software becomes exponentially more expensive to develop and support/maintain. Then if the bean counters get involved, budgets get cut and the software loses it's competitive edge and slowly dies. Remember Aperture?
Now we have folks using Final Cut that are gradually moving over to DaVinci Resolve.
Final Cut isn't really making the cut anymore. I still use it, because it's what I'm used to.
The bad news for Apple is you can use DaVinci Resolve in Linux, and all these old Intel Macs that are on the cusp of being made obsolete when software stops supporting Intel, can run on Linux. Personally I don't have any hope for Windows. If anything that will keep getting worse, because.. Microsoft.
P.s. Still Linux is far from close to delivering anything like Mac OS user experience.