@Red Leg, has put it perfectly to break the myth of red army poorly equipped, and abused as cannon meat during war.
To Add: in soviet military academies the tactis of retreat has not been thought untill well into the war, (because red army does not retreat), but this came with serious consequences togheter with fact that red army was removed from many capable oficers during stallins purges in 1930ties. This added to the losses count, in 1941.
But when things became tough, red army was learning fast. From putting capable officers in charge, like general Zhukov, to changing and adopting modern tactics, and implemetning retreat tactcis where necessary
Appropos, numbers, and industry in ww2, I found this in wikipedia:
tank production,
Germany (plus industry in occpied territories): 67429
Soviet union: 119.769.
airplane production:
Germany (plus industry in occpied territories): 133.387
Soviet union: 136.223
Artillery
Germany (plus industry in occpied territories): 73.484
Soviet union: 516.648
Source:
en.wikipedia.org
About the technology.
When the war started, germany was desperatly short on everything, including tanks. but due to brilliant new tactics and their commanders in first years of war they made noumerous victories, although for logisitcs they still heavliy depended on horses. (they started war with cca 500.000 transport horses, and by the end of war utilised up to 1.2 million).
For german panzers and panzer tactics, forming tank attack divisons nobody was ready, totally new concept. (Before the tanks were used only as support to infantry)
For example, French army at the beggining of war had biggest number of tanks in Europe, and french army was outmanouvered in 6weeks during battle of France.
Similar things happened in eastern front, at the begging of campaign. Soviets did not lack tanks. Soviets were caught by surprise, loosing terrtiroy and men, facing new type of enemy, but they had industry, production, still few of excellent officers, and they were learning fast, they had space, and were retreating slowly. They bought minimum time they needed to reorganise.
Apart from the lenght of war since it has started in the east (4years), and for better understanding the number of casualties in the east, it is also worth noting, that the longest front by lenght in history was eastern front in ww2, (accross entire euroepan continent from north to south)
When attack on russia started, eastern front from axis side it was kept by germany, italy, hungary, romania and all other axis power troops recruited from occupied europe. On russian side - only russians.
By 1944, eastern front stretched from Baltic sea, down to mediteranean.
Almost entirely kept by soviets. In later part of 1944, southern part of eastern front was given to Yugoslav partisans (allied army),from yugoslav border down to adriatic sea.
And in later part, of 1944 after romania and bulgaria were "liberated' they also joined forces with soviets.
So, in fact it was 4 years, of longest front in lenght ever, kept by russian on one side, and few other armies on another side.
One fact, remain interesting, and is to be highlited. war crimes.
Alhotugh, the german army were loosing ground steadily since 1943, in the same time concentration camp system was funcitioning flawlesly, practically till last moment, just untill few months before the end of war.Racial laws kept.
On ocupied territories, Policy 100 people shot for 1 german killed, kept. In attempt to try to control ressistant movements.
And as the war was steadily lost, more atrocities was invented, and ordered, in the lack of better solutions.
I have attached below, for another example, classified (Geheim) order to use explosive ammunition against enemy peronnel in the east. It is from the book, "German sniper 1914-1945" by Peter R. Senich. I dont see a practical or military reason for this, except for psichologcial effect, and intimadation of enemy, when the things became desperate.
(another order in writing).
Of course, this is a clear breach of Hague convention on ammunition in war, but illustaretes well the 3rd reichs war machine.