Most Mac Pro users have moved back to PC, or iMac's/minis just for iOS/macOS related dev, with most work being done on PCs.
Apple had a window where developers needed a heavy Pro Mac for iOS, nix development like python/ruby/etc, even Unity dev back when it was only on Mac (2007-2010 ish), it was also great to have a Mac after the 2006 Intel processor move as it was the sexiest nix and great for developers from 2006 on, but those days are over.
Somewhere in 2013, they just moved on from the cheese grater and Pro market that included developers and content creators. Now they want to regain it? There was so much momentum squandered here and hearing Tim Cook repeat "Post-PC" and Apple messaging that desktops were like trucks, only developers need them, caused them to move on, so did the pro users and developers. Apple even watered down their developer laptops and Macbook Pros, 17" screens were relegated to being 'lapzillas' and Apple went only mainstream. Content creators and programming were not something they focused on anymore after the iPhone took over, eventhough those influencers were always the focus. I thought they would use the iPhone and iOS/macOS platforms to get more people on their desktops as well, instead they went the other direction.
We used to be Mac Pro heavy now we just have iMacs/minis for the last mile or iOS/macOS export and testing with performance heavy beefy PCs for most of the day to day work. Additionally, taking your jet engine/trashcan new Mac Pro or iMac to the mall for repairs instead of just popping in a new video card or drive also sucks.
Developers can get two performance PCs for the price of one Mac Pro. Usually you can get more power out of both as well since Mac Pros from 2011 on were 1-2 years behind. There is no getting back pro users such as devs/game devs that had switched over and have now gone back to Windows/PC.