A few thoughts ...

1.) Be careful - the US courts have said that UNIX is not a code base or any one implementation - it's a set of ideas​.  That is the whole basis of the BSDi case and why in the end AT&T lost.  It WAS their ideas, but it just can not be a trade secret.  If AT&T had been able to claim it as a trade secret, Linux, Minix, Coherent et al would have been in violation too (which is why it was so silly to sue them).

2.) I believe that Linux is the current popular implementation of UNIX.   Yes it hurts my fingers by some of the changes, but it looks, smells and quacks like duck.   Linux uses the AT&T IP -- the published ideas.  All of us on this list, just like Linus, are 'mentally contaminated' by Ken and Dennis's core idea.   That's the basic fact and it not going away.

3.) Claiming LINUX Is Not UniX is like saying FORTRAN95 is not FORTRAN because its not like F2, F4, F77 etc...   I'd like to point out that in fact, modern FTN compilers can pretty much accept the old code - which pretty darned amazing (and thankfully I'm not a compiler writer).    But for guys like me in the HPC business, FORTRAN is still useful, as it pays our salary.   The thing we have to remember is that the target matured, and moved on.  It aint quite like it was and there is no going back.