A little conflict called World War II caused the demise of the majority of the Pre-War Colt commercial line. After the end of the military contracts, Colt fell on tough times during the transition to the commercial market. The .22 Courier was introduced in 1955 to fill the demand for a small-frame .22 revolver, which evolved into the .22 Cobra.
I took your original post as asking why the short-cylinder, steel, fixed-sight, 2-inch barreled .22 revolver was dropped from the line ("inventory"). Even if the same gun were made today, it would not match Pre-War quality. No Post-War gun of any brand matches Pre-War quality.