Greetings from the Reddit thread!
This overall attitude towards Vulkan astounds me. The API has been out for one month, and the drivers are far from optimized. Anyone working in Vulkan today should be doing so with the attitude of finding problems, reporting them back, and trying to make tools better. If you're going to evaluate the situation strictly at a business level, you shouldn't even be considering Vulkan. Come back in 2 years.
But if the mentality is largely business-centric, why is DX12 even a candidate? I mean, if there are technical constraints that make DX11 infeasible, knock yourself out, but I laugh at everyone who says Windows 10 is "inevitable". Yeah, it's inevitable as long as Microsoft continues installing it on customer's machines while they are sleeping. Windows 10 supporters are the most apologetic bunch I've ever met. The highest praise one can give Windows 10 is "well it's roughly as good as Windows 7 thankfully" because it was an escape hatch for the nightmare that was Windows 8. I plan to use Windows 7 for as long as I possibly can. When time runs out, I'll probably commit fully to Linux. You enjoy your mandatory updates and Microsoft spyware.
If you want maximum reach, using Vulkan should be a no-brainer. That opens the door to Windows 7, Linux, Android, and lots of crazy hardware. OSX will even be covered provided that MetalVK pans out. Heck, even Nintendo's next console is suspected to use Vulkan. Please don't fall into the trap of assuming that Windows 10 is where all gamers will congregate. Windows 7 is supported until 2020, and that is where many of us will be waiting.