Maturity levels are much lower than the 1950's...
For instance, I, myself, am what you would consider a "Millennial" (24)..
And I can agree that a good 80% of my generation and the newer generation after me are very self centered, they care about mundane, pointless issues, taking "selfies".. among st other things that point to emotional/mental immaturity and self absorbed/ narcissism.
It is a known study that this generation, many (not ALL - mind you) are very self obsessed and self entitled more than any other generation before us.
The way those in their 20's had acted back in the 1950's, most definitely is a big difference versus 20 - somethings now.
The maturity level on a mental and emotional standpoint both differ SIGNIFICANTLY... so the majority I would believe with those sort of faults are in absolutely NO position to raise a child, as well as marry that young because another reason?
INSTANT GRATIFICATION.
The generations of today are much more interested in reaping the full benefits without putting any actual work in.. (marriages for instance - most lead to divorce now versus back in the 1950s.. people do not have the patience, nor the maturity to work and solve issues with their spouses. - again, I believe this is where the narcissistic mentality steps in.)
It's quite frightening actually.
The second reasoning? The economy... it is also how expensive everything is now versus the 1950's.