Here's a choice for you all: (1) copyright as the IP protection for software, with cleaned up laws and procedures about "insignificant changes" and "derivative works" -- or -- (2) the current patent aystem, post CLS Bank , which has eliminated a lot of business method patents and some, but not all, software patents.
Is there anything about Unix -- then or now -- which is unquestionably better than Linux? And if yes, are the Linux versions of the features or capabilities a significant enough constraint to warrant using Unix instead? It seems that certain networking and NAS applications are measurably better on Unix (Netflix is still a big using of FreeBSD caching servers iirc) but can't Linux close the gap?
ZFS is an example of one that's recognizable, you can bolt it onto linux and it (now) works quite well, but it was integrated much more into Solaris.
There are also Unix platforms that fully support hot-swappable just about everything, which you CAN do with Linux but it's not as simple.
Most of that stuff is gone by the wayside now, Linux is "good enough".