England was beaten bloody. Germany lost, in total, well under a month's later production of warplanes, remarkably few per sortie. Its capacity to wage war was wholly undiminished. Germany could have continued as long as they cared to, but England was much closer to its limit than is widely recognized.

Much of the history of the war has had to be rewritten since Soviet records became available in the '90s. That has not penetrated far even yet.

"No Simple Victory" by Norman Davies goes some way in that direction. Aside from Atlantic naval operations, the western war was nearly a sideshow.

Russian mobile forces massed at the border needs explanation if not preparatory for invasion.