In this space it's not too unusual, really. It's not altogether unlike modern AIX or IBM i, which effectively only run on virtual machines managed by a hypervisor built into the firmware on PowerVM machines. Maybe less satisfying since it's less integrated with the hardware, but in a sense the paravirtual devices are kind of just another type of firmware/driver layer.

I kind of hope more (new) OSes adopt a similar model. Developing cool new experimental OSes would be easier if real hardware could be "ignored" in favor of just targeting virtio interfaces or something, and IMO that's where the most interesting OS dev is yet to happen. If you're mostly interested in hardware support and raw performance, I think Linux has "done it". But there's a lot left to explore, and maybe it's best to find a way to get Linux to do the heavy lifting.