partially right. MacOs came from the Next (a computer built from a Steve Jobs company). Next failed (this was after Jobs was fired from Apple) . Next OS came from Carniege-Mellon (introduced threads) which came from BSD ( introduced networking : TCP/IP, UDP). Ultimately they all came from Bell Labs (I worked there a long time ago). I was shocked when i got a MacBookPro about 10 years ago and it hung up, I could not use any Mac application to free it, finally opened a text window (to my surprise is was a standard Unix shell) and started typing in Unix commands that I used 50 years ago to kill off Unix processes and get it going. Apple has done a good job of making it look like they invented the work but in fact, the heart of MacOs (like 95%) was probably invented over years ago . Apple appears to have a graphical interface on top and called it their own. All of these systems above, had to and probably still do today pay a license fee to AT&T (who owned Bell Labs).
Linux is very different. A very smart person from Europe was able to mimic the Unix API and prove that the result did the same thing as the part Apple is probably paying a license fee for. He had to show he had no access to the Unix source code and do the work using existing literature. That was and is something. Not a simple task. So Unix has stood the test of time as Android also runs a Unix base from somewhere as does IBM (Linux base). My brain is getting old so I may not remember this all correctly but i think so.