Isn't that anthropomorphizing NT a bit? I mean, it's an OS, not a being. And the "promise" turned out to be mostly hype, at least in the 1995-1996 time frame. "A better Unix than Unix", "The Best Designed Operatings System", stuff like that is almost totally illogical, just an emotional appeal really.
If you read Helen Custer's "Inside Windows NT" you might have been excused for thinking you were reading about Mach 2.5, but I'm not sure what relation the OS described by "Inside Windows NT" (1st ed) had to the real Windows NT 3.1. So I'm still confused about what "promise" NT had.
Ugh, I remember what they promised in Cairo. What was promised wasn't realistic; making it inappropriate to consider NT as having failed by not meeting expectations.