Strange, I could have sworn the 109 and Hurricane were introduced in 1937, Spitfire and P-36 1938 and the P-40 in 1939...not years of difference there. High performance fighters weren't necessary until the U.S. was dragged into the war, at which time the industrial machine developed such "cheap" aircraft as the P-40, F-4U, P-47, P-38, P-51, B-17 and B-24, none of which used wood or fabric in their airframes unlike the Spitfire, Hurricane and Mosquito. And, I guess you could consider low production numbers of 13,000 P-40s with only 9 operational variants, 16,000 P-51s with only 4 operational variants, 16,000 P-47s with only 6 operational variants and 10,000 P-38s with only 7 operational variants, all produced in shorter time periods from concept to retirement, to be low production numbers compared to 20,000 Spitfires with more than 25 operational variants produced over a 10 year span. Didn't realize the U.S. was the only country using assembly line production, that would account for the aircraft manufacturing facilities in Britain, Russia, Germany and Japan.
There are enough Spitfires in AH.
Just want to clarify. As an example. How many P47 operational variants? I count 1 B model, 4 C models, 24 different D models, 2 G models, 1 M model, 4 N models. That totals 35 production model P47s.
And the first production Jugs rolled off the line 5 years after the first Spit. BTW it was an all metal aircraft. No wood in the production
Based on your description of production models, the Spit list would be the I/II as the II was built in a different factory then the I, similar to the P51B vs C. The Spit V, the Spit VI, VII VIII, IX/XVI and XII, XIV and 21.
So that's 9 production variants vs your 6 P47s and the Spit was in service 5 years prior to the Jug.