All art connects with events happening in society. The disturbances of the twentieth century, particularly the first half of the century, gave rise to many feverish movements, all of which wanted to define the world in a certain way in order to change it. "Alienation" is everywhere and nowhere in all of this, but there are few art forms that are built up (whether consciously or subliminally) from the sense that things are amiss. Noir is the only art concept that embraces that (in the various, protean ways that it does so).
Since noir is more of a construct than a so-called "indigenous art movement" (as some like to call it), we need to proceed a bit differently to trace its origins. Much of the story we know, but the emphasis is wrong, or has become self-serving.
I think the historical account of jazz you cite is a bit strained and over-generalized. "Cool" was just one aspect of jazz in the fifties. That it may have emerged as the best-known has to do with other factors that are not part of what the musicians were doing. Much of what happened in that area was initially driven by economic factors. The "big band era" was part of a semi-consciously temporary culture, part of a the constraints of a homefront culture. It isn't surprising at all that once WWII ends that it, like the record-breaking film attendance in that same time frame, withers away into a different configuration. Part of that had to do with African-Americans taking over that art form, and making it consciously subversive. It follows in the footsteps of other avant-garde artforms.
Hollywood was too big, too monolithic, and too tied into big business to ever follow such a recondite approach. It threw out its most radical innovators. Noir was subversive, but it quickly became a hot button issue when it pushed beyond the "social problem" film to "social justice" and political allegory/critique. The folks who'd forged into that area were marginalized and/or criminalized.
Sit tight...my theory and my history (of the other "noir" construct, as manifested in France, where it is more deeply connected to past literature and tied to emerging philosophies, and is more receptive to the emergent "arthouse" filmmaking that would grow up around it in the fifties) will be here for you and others to take issue with. Our time here would be a lot more productively spent, IMO, if we discussed alienation as a social/aesthetic concept and how it becomes prominent in literature--which is still the primary path to filmmaking today, just as was more intensely the case for it when sound came in, changing the dynamic of what narrative could do and creating a "realm of tonality" that could embrace the irony and cynicism that noir contributes to film.