Lessons Learned Pre-War Conflicts
 

Much is made of the fact that the Luftwaffe went to war in 1939 with highly skilled aircrew, courtesy of the experience gained in the Spanish Civil War.

British accounts especially make much of this, perhaps as a way of explaining away Luftwaffe successes in tactics in the early part of the war. And perhaps to emphasize how good the RAF was to defeat the Luftwaffe in the Battle Of Britain.

Either way, it is fair to say that the Luftwaffe did develop highly efficient tactics in fighter and ground attack.

But Italy, Japan and the Soviet Union too fought in several conflicts pre war. The Regia Aeronautica fought in Libya, Ethiopia, Spain and Albania prior to WWII.
Japan fought in China and Mongolia.
The Soviet Union fought in Spain, China, Khalkhin Gol and Finland.

Japan learned lessons from those conflicts to effectively employ them very successfully at the start of the Pacific War.

But Italy and the Soviets seemed to have missed a golden opportunity. The VVS especially, given it's combats against skilled adversaries.

Why is that?