In each and every documentary, book I’ve ever seen or read on the subject of WW II, I understood that the US (war) economy was huge!! In some cases it produced more of a certain weapon type than all other belligerents combined, I seem to recall. Then what’s the deal with this version of A&A? After Japan just eats up China, takes a couple of Russian territories and will probably eventually take India as well thereby opening up the way to even more IPCs in Africa it far outproduces the US. The same goes for Germany. In global at least the US gets a 30 (?) IPC bonus once at war! Many times Japan’s navy will simply be able to keep up with the US one
You should try the old school Axis & Allies Pacific- US starts with 80 economy!!