Generational scholars Strauss and Howe dedicated their lives to analyzing the four dominant generations of the twentieth century: the GIs, the Silent, the Boomers and the X-ers. Then, near the end of their collaborations they published Millennials Rising. The thesis of their whole canon of work is that each generation fulfills overall needs or niches from prior ones, and creates problems that future generations must solve.
The concept behind the Millennial Generation is that a national or global crisis will arise unlike anything since the GI’s Depression and WWII, and the millenials will rise to meet it. Or else society itself will falter. (Can you take a guess at how this thesis is already playing out?)