The biggest thing that makes the TrueOS distribution is using FreeBSD as the base. The FreeBSD kernel, the FreeBSD userland. What makes TrueOS different from every other FreeBSD distribution is the installer, the default install to ZFS, the integration with the newest FreeBSD graphics work and all the desktop environment (Lumina, SysAdm, other tools).
Taking out the FreeBSD kernel and userland and putting in the Linux kernel means you wind up with another Linux distribution, just one a different look and feel. In return you’d be giving up ZFS (yes, I realize there is ZFS on Linux, but does it really work as well as on FreeBSD?), you’d be giving up everything BSD. While you would gain hardware compatibility, I think you lose a lot more. You could always get the source code for things like Lumina and install it.
FreeBSD development lags Linux development, especially in areas like new hardware support. Getting more people involved helps, but the people that can do the work have limited time and doing kernel level programming for new hardware is not something you can pick up overnight.
Turning TrueOS into simply another Linux Distribution would not advance FreeBSD. But since the licensing on all the bits allows anyone to fork it, I could be wrong.