No that's not an isolated case at all. There are many studios for example that have 3dsMax on their pipeline and that is only available on windows.
Regarding GPUs windows offers both openGL and directX support and that's a huge advantage for game developers, and you have a lot of choices and solutions for GPU hardware. High end solutions for laptops from Nvidia are now very accessible and offers competitive performance that a few years ago was pure science fiction.
Most professional 3d software are taking advantage of nvidia GPUs right now, and the support is far more superior on linux and windows platform. Current mac versions of these sofwares are already lacking features when compared to windows/linux ones, and many third party extensions will never be released.
There are many reasons for this, one is simply that pro nvidia solutions are officially discontinued by apple (classic macpro), proper portable solutions are dead, OSX is pretty much developer's nightmare with so many frequent releases that breaks so much stuff, and OSX openGL support is lacking and underperforming. Let's not forget the Retina nonsense where you sacrifice performance, system resources, screen real estate and responsiveness for much more useful hi res dock icons
![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Mavericks was the point of no return: broken memory management, broken network support, broken application support and so on
nobody sane of mind is running a full 3d pipeline past Mountain Lion as you cannot afford to waste time on stupid problems during production.
Many big studios now prefer to give the artist one Windows workstation for Adobe software and a Linux workstation for the rest of the 3D software packages and customizations.