True, Final Cut Pro is supposed to be a terrific product, but for a niche market (the video editing vertical market). It's irrelevant to 99.9% of the workforce. FCP is well known by Mac users because they've always been a pioneer on this market, but the vast majority of vertical markets are Windows only, or best with Windows. One I know well: Wi-Fi site surveys. Two good products exist: AirMagnet Survey and Ekahau Site Survey. Only Ekahau has a Mac version released only one month ago, still in beta and lacking half the functionality of its Windows older brother (and the Mac version won't get them any time soon because of OS X limitations). Or the CAD market: yes there's a Mac version of AutoCAD for instance, but I've yet to meet anyone using it. 3D production: lacking OpenGL performance and limited hardware doom the Mac here. Etc. So video production is more the exception than the norm as far as vertical markets are concerned!
Well, if Unix is important, one could also virtualize some Linux variant under Windows. (Or even virtualize OS X, although that's unsupported so not necessarily a smart move for work.)
Now I'm playing the devil's advocate. I wouldn't be on this site if I didn't have a Mac and like OS X, or rather used to like because I'm not convinced by the way Apple makes evolve their non mobile OS and hardware, and I'll have fully switched to a PC before the Mac has definititely become the Apple II of the modern era. But I don't think productivity is the main driver behind a switch to Mac: ease of use was probably it (which indirectly helps with productivity, granted). I use a past tense because Windows has come a long way since version 3.1, and overall I find Win 10 and macOS to be equally easy (or difficult) to use.