I believe giving the name (quarter-life crisis) for the transition period from childhood to the adulthood is just slapping a different name on a part of life that has probably existed for awhile. However, in the past it was more common for children to stay with their parents until they entered a marriage, therefore coining a term for the new dynamics of this age group may be appropriate.
It doesn't matter if you are 25 or 75, each stage in an adult's life goes through some kind of change. A quarter-life crisis isn't a crisis--young adults simply have a change of heart and go in a different direction during or after college. Younger people are also trying to find their identities in a complex world full of hope and peril in the job market. Do they play it safe or take chances? With so much to focus on, no wonder young adults have a "quarter-life crisis."