Not to get political but I always thought it was a mistake to make "modern" samba GPLv3. All it did was make all these hardware vendors either stick with the older GPLv2 stuff or... I dunno what else they can do besides write their own implementation.
Samba is too much of an "infrastructure" codebase. It should have been BSD licensed. Vendors would have strong incentives to merge changes back into the mainline... none of them want to have their own wacko implementations.
Samba operating on the application layer and working the way it does means you can totally ship a computer that runs Samba with the immediate tooling around Samba also bring GPLv3 and the rest being proprietary.
Samba is too much of an "infrastructure" codebase. It should have been BSD licensed. Vendors would have strong incentives to merge changes back into the mainline... none of them want to have their own wacko implementations.