What caused the rampage of crime is attributable less to a loosening of taboos against porn, and more to the welfare state and its effect on men on the low end of the bell curve.
Before the welfare state, lower-class men had a purpose. They worked. They supported a wife and family, even if very modestly. A prison term would preclude a respectable life, so that was a disincentive against crime.
Now, there's welfare. Women lost interest in poor-but-honest men who could not provide better than what Uncle Sugar could give. Having part-time affairs with thugs was more exciting. A thug with cash could take her places, while grandma stayed home with the kids, supported by welfare.
If being an honest man does not get you the love and respect of a good woman, and the joy of living with your kids, then there is far less incentive to be an honest man.
What caused the rampage of crime is attributable less to a loosening of taboos against porn, and more to the welfare state and its effect on men on the low end of the bell curve.