It became a cliché. The kind of easy shorthand you can use to quickly label something as Noir. Just add “Big” to the title. It’s true, an inordinate number of noir films are Big films, but many are also some of the best the genre has to offer.
Of course, not all. The Big Town series are pretty dull. Many Big movies are just forgettable: The Big Tip-Off (1955), The Big Fix (1947), The Big Bluff (1955), The Big Boodle (1957), The Big Boss (1941), The Big Chase (1954), The Big Caper (1954), The Big Punch (1948), The Big Shot (1942).
But when they are good, they are damn good.