WMI can only surface information that the underlying hardware provides, and that Windows passes along. The ComputerSystem and BIOS classes in particular are pretty old, dating back to Windows NT 4, and haven’t been significantly updated. That’s why they don’t contain that kind of detailed information. I’m not aware of anything else built into WMI natively that would get you that information, though. Doesn’t mean there isn’t something… just haven’t seen it myself.
It’s entirely possible that the manufacturer provides MOFs that extend WMI to provide additional classes or extend the existing classes to provide that additional information. But Microsoft usually leaves it up to the vendors to do that.
I’ve been told in the past that VTx is deliberately not exposed through WMI for security reasons, but I’m not sure what those reasons would be. That was an HP engineer who told me.