Earlier quoted context omitted.
If you want to virtualize something with good performance on desktop windows you use Hyper-V; if you want to do it on mac you use Apple's Virtualization Framework; if you want to do it on Linux you use KVM. Desktop virtualization products used to bring the secret sauce with them; now that every OS ships with a well-integrated and well supported type 1 hypervisor they have lost much of the reason for existing. There's…
They still need to. You are glossing over the fact that you need to provide device access, USB access, graphics, and a lot of things that are not necessarily provided by the "native" hypervisor (HyperKit does not do even half of what Parallels does, for instance).
I didn't say they have no reason to exist. I indicated they are moving towards becoming UI shells around standard OS features and/or other commodity software, which they are. Look at UTM, for instance. Even VMware Workstation and VirtualBox on Windows use HyperV under the hood if you have HyperV or WSL features enabled.
While everyone still seems to be busy disagreeing with me because of , I'll mention that HyperV does have official support for transparent GPU paravirtualization with nvidia cards, and there are plenty of other open projects in the works that strive to "bleed through" graphics/gpu/other hardware acceleration api's from host to guest on other platforms and hypervisors. With vendors finally settling around virtio as somewhat of a 'standard pipe' for this, expect rapid progress to continue.