Why is DirectX 11 Still a Thing?

When it comes to this subject. I’m knowledgeable enough to grasp the bigger picture, but still dumb enough to ask potentially dumb questions.

Years back everybody was saying it was only a matter of time before Vulkan displaced DirectX as the standard API. Yet, that never seemed to play out quite that way.
Is/was Vulkan akin to Linux in that regard? Where there were many people who swore it’d replace Windows at some point, but today everyone pretty much agrees that won’t really happen?

Will some derivative of DirectX be the main one for the foreseeable future, or will something else eventually come along?