With Japan reconstruction, USA gained a generations-long economic and strategic partnership, the value of which simply cannot be overstated. Imagine the instability there would have been in that region, had we not aided Japan in her reconstruction.
The question isn't "how did that work out for them?" Rather it's "what would have happenes if they hadn't?" or "what would have happened had they struck a year earlier when the Pacific Fleet still mainly had Brewster Buffalos?" The longer Japan waited, the lower their chances of victory. By 1940 it was clear the USA was not going to tolerate Japanese expansion into the Pacific. We would fight a proxy war in China using Chaing kai shek or another puppet while fortifying the Philippines and restricitng Japanese trade. Attacking Pearl Harbor wasn't a good idea, but Japan didn't have a lot of food options to become the dominate power in thr Far East.
GDP? It is not feudal era. They are unwritten military colony, such as Western Europe. Ask Soviets if that did not matter in the 50s.
@Chinatown I envy you the opportunity to serve on that ship and the uniform you were wearing. Respect to you, sir! I may sound too bombastic but still think that a manhood is better defined by serving in military.