The Buffalo still performed useful bomber interception and could hold its own against the older Ki-27 Nate. The balance changed when enough newer Ki-43 Hayabusa fighters, known to the Allies as Oscars, arrived. Commonwealth Hurricanes offered only limited reinforcement and lacked the complementary Spitfire force familiar from the Battle of Britain. Hawker's attention had also moved toward the Typhoon and Tempest, another example of older fighters receiving less development. The Buffalo's poor 1941-42 position combined inadequate type training, rapidly improving opponents, and a wider Far East defence crisis.
Notable Point · 36:21-38:10
How the Ki-43 changed the Buffalo's air combat prospects
The changing Japanese fighter threat explains why an aircraft still useful against bombers and Ki-27s became badly overmatched once Ki-43s arrived.