True, though for most game/graphics developers you're never interfacing directly with the graphics API, you'll let your chosen engine/library do the heavy lifting.
It does have the downsides of increasing the barrier to entry for custom/bespoke engines but those edge cases seem to be covered well by DXVK.
Even so, having more software natively supported will always be a good thing. Half the reason why people drag their feet on switching to Linux is because of the lack of support for their favorite software.
Right? Dude Vulkan has impressed me a bunch lately. I use it for Deadlock and it feels much smoother than the streamers I see using DirectX, which is crazy since Deadlock is super early alpha. More stuff needs to support Vulkan