Because:
1) Windows 10 Pro isn't THAT a big innovation in the first place, compared to Win7. (And I tried it.)
2) Touch-enabled screen is overrated and only marginally useful (unless the laptop is a convertible).
3) 4K. So what, when most apps don't scale and even some parts of the OS itself can't scale for that resolution.
4) Beautiful Windows laptop. Yes, there are nice ones but unfortunately, most of the them still have terrible trackpads and/or keyboards.
And for the record, I use both and I'm still waiting for THE quality Windows laptop that I would gladly purchase to replace the existing one. (Yes, yes I have looked at the Dell XPS, supposedly the best Windows laptop out there; but it still doesn't cut it for me -- while the hardware is great, software still has lots of rough edges.)
So for now, I still enjoy using my MBPr much more than my Windows laptop. I have been using Windows since the Windows 3.1 days. I appreciate its eco-system, it has served me well but now, for sheer enjoyment of using a computer to do some web programming, I use the Mac unless there is some technical reason for me to use Windows.