"Mac OS has dropped from 7.66 to 5.85." (-1.81) "Linux ... from 1.68 to 3.37" (+1.69)
I speculate that many of the ex-Mac users are moving to Linux.
It also begs the question, what did Apple do wrong in the last 2 years?
The neglect of user needs in the hardware department doesn't totally explain the software shift, though.
Also a decent range of graphics options, as well as large RAM options. I don't feel any of the current 'pro' level hardware offerings come anywhere near the requirements of a professional, at least in terms of costs when compared to other options from smaller vendors.
I cannot think of a single enterprise environment (including education) that upgrades to the latest macOS version on release day (or year) anymore.
Many I know are still running El Capitan and will move to macOS Sierra when High Sierra comes out due to core apps no longer working / lacking updates to the latest macOS offering.
Maybe they should switch to simply 'macOS 2017' then 'macOS 2018'. Not really working for MS but an OSX update is less of a significant update than a Windows major version.