Well Mac market share has only improved as more models move from Intel to Apple silicon, so...
We've had a boom in personal computer demand during the pandemic and Apple seemed to have been less affected by the chip shortage than their competitors (being good at logistics, having your best-selling computers using your own system-on-a-chip and being immune from the GPU price/supply madness help).
Apple Silicon is at its most impressive in low power applications like the MacBooks, which blow comparable PC laptops out of the water (...and give non-comparable laptops a run for their money).
However, we're talking specifically about higher-end Mac Desktops here - which were always the least popular Macs, and which don't benefit quite so much from Apple Silicon's low power advantages. Apple make impressive claims for the Ultra, but I'm betting those are based on Mac-optimised software that makes good use of the media engine, neural engine etc.
And if I only use macOS, I should care why?
If you just use FCPx, Logic, MS Office, maybe Adobe CS and browser-based Apps on mid-range Macs you may be fine.
Otherwise, you're relying on third-party developers to keep supporting and improving the Mac versions of their high-end Pro software, despite most now being available on PC and the PC market offering far more potential customers.
If Apple relies on established MacOS customers sticking with the pro Macs and
doesn't succeed in attracting new users from PC land, then you're looking at a pool of users that is continually shrinking as people get picked up by PCs that offer more bangs-per-buck or even just a hardware solution that is better tailored to their needs. That leads to a vicious circle - fewer customers, less software support, more customers jumping ship. Sooner or later, the pool dries up.
Back in the late 80s/early 90s, Macs could do things that PCs - when Windows was still basically a DOS shell, and not even full 32 bit - simply couldn't, which is how they got established in pro audio/video*. Those days are long over.
(*although, interestingly, the first viable looking personal computer-based non-linear video editing system I saw ~ 1990 was running on an ARM-based Acorn workstation, which was briefly ahead of the game in it's ability to play moving video from disc. We're talking about building an edit decision list from grotty-looking, quarter-screen 'proxies' that had been compressed by a lab using specialist hardware, of course, but it was still better than a Mac or PC could do).