Actually none of the belligerents during WW2 where any good at logistics.
- Wallies could barely supply their forces in France less then 500 km from port, across a good road and rail network.
- Red Army had to take a months long break after Bargation.
- Japan and British were stuck in Burma because neither side could get supplies or numbers to the front.
- Japan failed to get deeper in China mostly because of logistics, and much the same could be said for Chinese counter offensives.
This leads me to the fact that at the time of WW2, besides the general lack of understanding of Logistics, that the infrastructure was simply insufficiently developed to sustain million man army's on the move.
Also please note that during the 1st Golf War the US forces took months to build up a supply base in Saudi Arabia, for an advance that was planned to go no further than 400km. And that was while they were unopposed. So even today with full understanding of logistics, it still requires massive effort and investments in infrastructure to supply a million man army even if for only a short time.