I’m reading a history of the battle now. The one thing that seems to be developing is that the Russians were profligate with their troops. I suspect that mentality was behind the jaw-dropping casualty figures. That and the German Tiger 1s.
It’s like the German general said during the early days of Barbarossa when it appeared the Germans would wipe out the Russians.
“It’s a fight between an Elephant and a bunch of ants, the elephant will kill millions of ants, but ultimately the sheer number of ants will eat the elephant down to the bone.”
One more important detail. In the mid to late 30’s,stalin’s top commanders warned him about hitler’s military ambitions and the need to improve Soviet military. stalin was very busy at that time with repressions and killing of the Soviet military elite. This act alone caused millions of victims among civilians and military personnel during WWII.