Was the B-29 really a wartime invention?

Was the B-29 Superfortress a genuinely wartime aircraft project?

The specific B-29 matured during the war, but its pressurization, range, and bomber-development foundations were already being assembled before the United States entered the conflict.

The B-29 Superfortress separates a finished wartime aircraft from its technical ancestry. Boeing had explored pressurized long-range bombers from 1938, the U.S. Air Corps issued a formal super-bomber requirement in December 1939, and Boeing submitted the Model 345 in May 1940. The aircraft's September 1942 first flight therefore marked the wartime maturation of a programme rooted in years of earlier research. Mobilization accelerated integration and production without creating every enabling idea from scratch.