If you look at the raw numbers of how Boomers prospered in their life cycle and compare it to the trajectory of Millennials it tells a clear and jarring picture. Even more so for Gen Z which explain why they are eschewing capitalism at far greater numbers than Millennials ever did. Note: all of my comments applies to a lesser extent to GenX as well but AOC was referencing Millennials since she is one. The point is if you look at the trajectory from Gen X onwards it paints a picture of decline in most aspects of life.
WWII is really the Silent + Greatest Generation and does not excuse the decline that started after Boomers.