Usually I do not complain about low IPC for allies. Allies are able to win the game even with an Axis bid, in Revised. It is a question of using them effectively. Having more IPCs with USA is worthless if they are spent in useless way. Spendig wisely what USA have is sufficient if the USA player have a soundly plan.
I am with Krieghund here: National Objectives add to these initial values. Moreover do not forget the relative strategic and geographic position of the nations involved in the war. Allies had won the war also for Strategic and Geographic factors that are present also in A&A map.
Furthermore UK was already at war by September 1939 while USA were still out of the war. Sure they had a great industrial capacity but the efficiency of a weapon is not only in the weapon itself. The hand that holds it is very important. (If I gotten a Ferrari Formula One car it was quite impossible for me to win the Championship.)
After operation Torch the USA Army advancing in Tunisia had difficult at Kasserine pass against experienced Axis units. They were well equipped but they lack the experience.
So the value is acceptable for USA. The IPC and the units in revised are not strictly related to the quantity but they have to represent also the qulity of the units. In 1941 UK units were more experienced than USA units.
I am supposing that this value had been playtested and are part of the great picture for balancing the game.
Instead, the problem could be for 1942 set up. Given the fact that the IPC value are the same and the Axis starts with more territories, Allies should have a less IPC than in 1941. I am wondering if the national objectives are different for 1942 setup… ???