I agree that Uni wrote itself into a corner with the "House" films, though their continuity was broken by the A & C comedies, so in theory they could have said to themselves circa 1949, "hey guys, we had a good thing going there, let's bring back the old monsters", but they didn't. As to why this thought didn't seem to occur to them, or if it did they discarded it, is a genuine mystery. Horror had saved them more than once in the past; they'd made a bundles (actually bundles) off of horror.

Leaving the noir-replaced-horror matter aside for now, it does seem that the new world that was emerging after WW2 must have seemed daunting enough. Indeed, after the Nazi death camps and Hiroshima, who needed fictional monsters to get spooked? Then there were the real world issues of Stalin's taking over of eastern Europe and the rise of Mao and his gang in China. I'm with those who've brought this topic up before. Real world issues were pressing enough in the postwar era, and it's difficult for us to imagine how things felt back then, in 1945-46, when not just Uni but every major studio just stopped making horrors.

My old issue: the demystification of Europe. It wasn't a romantic place anymore, not after the world war. Many American soldiers had served there, had fought in and around castles and cathedrals; no monsters; German soldiers, yes, but not vampires and werewolves. It was a matter of "you can't go home again". Americans couldn't view the Old World after the war as they had before and during it, as a faraway place of ancient stone buildings, superststitious peasants, lonely mountain roads, Grimm's fairy tale forests, blind hermits fond of cigars and violin playing who lived in thatched huts, gypsey fortune tellers,--in other words, the Universal backlot. Or Warners, Metro's or anyone else's. It was over. Old-time horror was like the flip side of the operettas so popular in America prior to the war, largely forgotten and ignored afterwards; Rosalie and Naughty Marietta come to mind. Gone. It was perhaps almost unbearable for people to realize that this Europe perhaps, just perhaps, never existed in the first place; that it was all fantasy, the imaginary world where our ancestors (more or less) supposedly came from. How could that world have produced Hitler, Mussolini and Stalin?