Ask HN: Why does libvirt/kvm get so little traction?

It seems like vagrant, docker/machines, etc. Have little and/or minimal support for libvirt/kvm.

Is there a reason for this? I would mostly like to use that (instead of VirtualBox, just by preference) but it seems like that generally isn't possible. Is libvirt hard to deal with (technically), Linux-only problems, something else?

I'm not in anyway trying to be negative/disrespective of the projects, just trying to gather an understanding.