Why OS virtualization is not possible?

As stated in the eewiki page, no OS virtualization is one of the basic requirements:

Could someone explain to me why it is not possible? Thank you so much.

I state that because, VMware/VirtualBox/etc usb-flash-host-driver is

Over the lifetime of those applications, getting them to properly "dd"
anything to specific flash location is not possible on 100% of end
users systems.

Feel free to use any OS virtualization software, but if you ask any
questions on why something doesn't boot or the OS is borked, they will
be ignored..


I am all in for efficiency. Glad to know VM is that bad.