The web/webapps/mobile helped lead to this era of "desktop PCs" (to include laptops) where the browser mattered more than the OS. It allowed Apple to become resurgent in the desktop market because OS compatibility mattered less than ever.
It's not weird that it led to Apple regaining _some_ market share because clearly there was demand for the Apple/MacOS/OS X experience that may have been tempered by incompatibility in the pre-webapp days.
What _is_ weird, and nonintuitive, is that the (by all accounts) higher-cost vendor would be seen as ascendent in this market. All the more weird for two reasons:
1. The Apple experience, at least on the OS side, matters less and less in the webapp world.
2. Apple isn't trying, either! They're seemingly doing their best to abandon and alienate their desktop OS users. A decade or more of stagnation or regression in features and usability, capped off by Tahoe this year.
It feels like Apple and Microsoft are just waiting for the desktop OS to die, waiting for mobile to take it over; so we can all just shut up and stop asking for filesystems and terminals so they can sell us iPads and Surfaces, and they can finally be free of this ancient burden of selling desktop computer OSes.
And the consumers keep buying the stupid things, demanding product in a market that the vendors don't want any part of.