What are you trying to say? Are you saying that the commercial Unix licenses (to Sun et al) were only for a nominal price? Or are you saying that they were
not for a nominal price, hence the BSD suit?
I agree that "the context changed" - IIRC, when the AT&T consent decree expired. That was 1982. Sun Microsystems was also founded in 1982. It was based on BSD, which had to go through the lawsuit to be proclaimed, essentially, a cleanroom Unix.
When Sun licensed from AT&T, (early 90s?) it was (I presume) at market price.
All that detail doesn't change my point: People cloned Unix because they wanted Unix. There wasn't a Berkeley VMS, not just because VMS was expensive, but because nobody wanted VMS that badly. (Why clone the thing you're getting for close to free, anyway? Doesn't it make more economic sense to clone the thing that you can't afford (VMS or OS/360), and pay the nominal price for the almost-free thing?)
People cared about Unix in a way that nobody cared about VMS or OS/360. Perhaps the ability to see the source code was part of that. But the story you're telling seems far too simplistic.