Personally, the reason I believe Axis is more popular, Is due to how much less micro there is in the faction then Allies. Allied units are pretty heavy on the micro tax, as tbh thats really the only way to make allied armour truly effective. Even the pershing sometimes feels like paper.
*Laughs in riflemen, penuls, cons, IS blobs (they are very micro intensive you know)
Any faction tanks requires micro, only those with decrew can use the magic key called SHIFT to queue the decrew, repair, and mount up repetitive task. Thats not worth even mentioning.