If we ignore the mistakes of the past...
You can learn from the mistakes of the past without shitting on an entire generation with generalizations.
The greatest generation in the US was the same generation as the Nazi generation in Germany.
The greatest generation in the US was also the same generation that rounded up loyal Americans of Japanese descent and threw them in camps.
No generation is without its flaws, or victories. Because one thing never changes from generation to generation: The human condition. You know what else is unchanged? Shitting on the previous, and subsequent generations while idealizing the generation once removed. We tend to blame the previous generation for all the world's ills and slander the newest generation for their naivety/laziness/whatever. Meanwhile we pick a generation from history and idealize it while forgetting all of its flaws.