Art follows philosophy. Entertainment imitates art, and society and its members unconsciously follow art and makes entertainers role models. The aesthetic and behavioral paradigms started by Playboy have had a rippling, cascade effect which has swamped prior sexual morality to the fringes and has made mercenary sexuality a defining feature of the USA. For verification, just read samples of newspapers for the last forty years.
Sorry, I just think that blaming a magazine for these events is silly, and confuses the disease with one of its symptoms. There were pin-ups in Police Gazette at the turn of the 20th century. I remember a gag (that I didn't 'get' but understood to be one of those mysterious adult jokes) on a TV sitcom that revolved around the pictures in Esquire. I don't think Playboy even existed then.
I submit that this stuff was already on its way for other reasons, and that Hefner just happened to be the guy who showed up at the right time to make money from it. That makes him a visible target for critics, but to attribute a sea change in public morality to some pipe-smoking libertine in Chicago is giving him too much credit. The country was ready for Hefner when he showed up. Had he come by with the same magazine a decade earlier, no one today would even know his name; he'd be a blip in the Cook County bankruptcy records.