Android with Vulkan support means Android 7, currently available on 1.2% of worldwide devices, hardly a market worth spending resources on. Also it is an optional API, Android 7 compliant devices aren't required to actually provide it, apps are supposed to check it.
Windows support is done by GPU vendors, not Microsoft and is only supported on Win32, not UWP applications.
Sony doesn't plan to support Vulkan, PS* APIs are much better.
Nintendo did introduce support for the Switch, but they are so confident on it, that they also have NVN, which offers much better control over the hardware.
"NVIDIA additionally created new gaming APIs to fully harness this performance. The newest API, NVN, was built specifically to bring lightweight, fast gaming to the masses."
I couldn't tell you how much impact this actually has, but Vulkan/D3D12/Metal have to be conservative with pipeline state changes, and have to manage the layout of various hardware data structures for you.
They've gotten partway there with things like D3D12 descriptor heaps, but hardware-specific APIs just don't have those limitations.
Apple is the only people who haven't because of Metal.