Wasn't there a discussion of SP Art not being available in this build? And now we see that the Axis and Russia lack Art regiments in 1941?
Can you check to see if there are any Arty brigades anywhere in this build? In 1941, the US should have a few.
Could explain why the OOB seems incomplete, if this build didn't include artillery.
And on another note, given your lack of officers, wouldn't it make sense to avoid building new divisions? And devote all your IC to upgrading / reinforcing / supplying what you have?
As for the OOB, perhaps more divisions should be considered reserves at the scenario start?
It's pointless to double guess why - and where are you getting it from that SP ART was ever "unavailable"?
The real and only reason is that it's Paradox and everything gets done at the last minute. There is probably going be a couple pages worth of OOB fixes in the first patch alone, if history is any guide.