I assume by "tail end of the American dream" you mean the 90's... I was probably roughly the same age cohort around the time of the Iraq war, and was completely opposed to it.... Although I guess it wasn't so much out of a sense of "losing something", because when you're a libertarian the world is so far from your ideal anyways that there's kinda only room to grow.
Hard to understand how good certain aspects of the 90's were at the time, except in the rear-view mirror...
As for young people, the nice thing about them is that they're much more given to hope and optimism than older generations. A transformational figure like Obama (or Trump for that matter) could, for good or ill, mobilize them... I think we just haven't seen that person emerge yet.
Although my hope would be that people get mobilized around social movements rather than people, because it's always better to champion an idea than a person...