IMHO it was an architecture far ahead of its time --- basically a hypervisor running existing DOS in VMs, with all hardware passed through by default. If they kept at it instead of abandoning for NT, by e.g. increasing protections for better isolation and reliability, while still passing through where performance mattered, we might've gotten Microsoft's take on Xen.
Would HyperV and Virtualization Based Security be that take? I suppose it’s taken very far on Xbox and VBS is enabled by default on most Windows systems.