Originally, Strauss and Howe thought the Millennials would rise to face the crisis as the Civic-Hero GI generation did earlier, but it doesn't look like that will happen.
There is a cycle, but the actual details don't always match up with Strauss and Howe's ideas about when a generation starts and ends.
Truman and Eisenhower, for example, are part of the same disillusioned Lost Generation as Hemingway, Fitzgerald, and Faulkner, rather than part of the Heroic GI generation. Jefferson, Madison, Monroe, and Hamilton are all part of the Heroic Republican Generation, but Washington, John Adams, and Patrick Henry are part of the Liberty Generation, which is similar to Gen X and the Lost Generation as a nomadic and disillusioned generation. Most people would find Washington or Eisenhower more heroic and foundational than their successors.
On the other hand, it does kind of make sense that Joe Biden is part of the conformist, non-confrontational Silent Generation and Bob Dylan, born one year later, is put in the prophetic Boomer Generation (demographers would usually put Dylan in the Silent Generation).