FreeBSD is not "compatible with Linux", it provides a way to run Linux applications under a Linux-like syscall environment. What you're suggesting is as if you could load Linux kernel modules into the FreeBSD kernel.

The issue with NT is the driver ecosystem. You'd have to reimplement a lot of under-documented NT behavior for NT drivers to behave themselves, and making that work within the Linux kernel would require major architectural changes. The userland is also where a lot of magic happens for application compatibility.

> What you're suggesting is as if you could load Linux kernel modules into the FreeBSD kernel.

Afaik, you partially can.