Low income levels and high debt are just two of the factors.
...adults under 35 have a savings rate of -2 percent, according to Moody's Analytics. The report said that in 2009, the savings rate of those under 35 was 5.2 percent.
http://www.theatlantic.com/business/archive/2014/11/why-arent-millennials-saving-money/382634/