The Federal Reserve didn't seem very comfortable using QE, but felt it was needed due to the depth of the crash. We were lucky we didn't have a repeat of the 25% unemployment of the 1930's. There's no law of nature that says all slumps are repairable. When things get bad enough, the masses rise up and demand socialism, because "average" socialism is usually better than crashed capitalism. Eating bland food and standing in line is better than death.
Short of a meteor/nuclear strike, I can't imagine mass starvation in the US, we simply produce too much food. Without QE, there would have been economic slowdown, banks would have been shuttered, but IMO life would have otherwise carried on as normal.