I thought sun was in partnership with AT&T when system V came out, and https://en.wikipedia.org/wiki/History_of_Unix appears to support that idea, but my first-hand memories have dimmed with time (cause it's not something I care about that much) and you may well be right.

I do remember, um, liberating an overlooked copy of system V/386 on 5.25" floppies that I found in a storage cupboard when I worked at PC Magazine in 1992 :-)

If you have some time to refresh memory.

"A Narrative History of BSD by Dr. Kirk McKusick"

https://www.youtube.com/watch?v=ds77e3aO9nA

"Unix came into many CS departments largely because it was the only powerful interactive system that could run on the sort of hardware (PDP-11s) that universities could afford in the mid '70s. In addition, Unix itself was also very inexpensive. Since source code was provided, it was a system that could be shaped to the requirements of a particular installation."

http://www.princeton.edu/~hos/frs122/unixhist/chen.htm

Thanks, this looks enjoyable and informative.