As a Surface Pro 3 user, who saves a Macbook Pro for heavy lifting (like video) at home, I can safely say the MB is getting replaced with the Surface Book. Depending on in-person use, it might also replace the Surface Pro 3. I typically watch Apple's and Google's product launches, have to to say this event was concise and unveiled products in a great forward moving momentum. Solid work Msoft marketing team!
I meet an increasingly large number who use Windows now. They're often people who used to use Mac Pros and switched to PC towers when that fell behind in price/performance.
The new Mac Pro is very expensive compared to what you can assemble in a PC tower, and the tower gives you a lot more flexibility.
As others have said, there's plenty of video editing software for PCs. The main one that's missing is Apple's Final Cut Pro (which Apple bought from Macromedia, though it's changed a lot since then).
For the parts of the industry who run Apple's Final Cut, yes - but Avid Media Composer, Adobe Premiere Pro, etc also exist and are used by many video pros without the same platform restrictions as Final Cut.
The Adobe suite works on both platforms, OSX and Windows. The files can be shared. I have not seen performance or workflow improvements on either. If anything, Photoshop on the Surface hardware is great for sketching and painting.
