We have to understand that Russia didn't stay in the war until the end. After the Revolution of 1918, Russia gets out of the war. On the other hand, the Russian Empire had about 5.5 million soldiers wounded or dead. This is about 30% if we put in a chart. Compared to the other countries involved in the war, Russia was the one that less suffered.
It caused the civil war. The industrial revolution in the North, during the first few decades of the 19th century, brought about a machine age economy that relied on wage laborers, not slaves.
