I'd like to think you overstate the case.  However...

 As a guy who reached 30 in 1976, I know that many of my very common, accepted behaviours back 40 years ago would not be tolerated today by many young women and would definitely put me at great risk if I became a husband or significant other today.  I watched as many five to ten years older than I--both men and women--were caught in the swing of the social permissive pendulum.  Both former wife and I were victims of swift change, too.

But everybody's happier now, right?  The crazy 70s are behind us. We all know  expectations around behaviours, right?  I have a suspicion...

Many of the "live alones" and "over 30% between 20 and 30" living with parent(s) might actually be choosing these lifestyles (if that's the word) out of CHOICE and refuse to take the risk--and they grew up with the "new behaviours."