In my opinion, it's largely the result of poor economic conditions and rising inequality endemic to a broken system. Young people today are keenly aware that they will have significantly lesser quality of life than the generation that preceded them, while simultaneously having to work much harder to gain a fraction of it. Communism may have fallen over in the Soviet Union, but it looks as if Capitalism is destined to fall much the same way. It is just taking a little longer, and so, the fall will be a little harder too.