WWII query: Why did France surrender so quickly while Russia held out for years?

Next month, this column will be moving to another platform. But before we go, in celebration of eight happy and productive years at Foreign Policy, here are the most popular items ever to run on the Best Defense. This item, which originally ran on June 2, 2015 is number 1. 

I’ve read tons of books on World War II, yet I realized the other day that I don’t know the answer to this question. British intelligence expected France to hold out, but the USSR to collapse in a few months. Yet the opposite happened. Why?