The manpower requirements being out of proportion to real life are due to game balance. I asked similar in a different thread. if they were IRL proportions some units would likely never be built.
"A good plan, violently executed now, is better than a perfect plan next week." - General George S. Patton, Jr.
"Do, or do not. There is no try" - Yoda
"Do, or do not. There is no try" - Yoda