That is a valid point. But I will say in rebuttal that while the labels did perhaps affect some people financially with less sales in the short-term... there was no long-term "slippery slope" of stopping people from producing said products in the future. We did not see the brakes of our societal mores get slammed down. And in fact... when we look at the things that 2 Live Crew or ADC did that were considered "offensive" at the time... they are quaint in comparison to what we have right now. The overt sexuality of "As Nasty As They Wanna Be"? You find things more overtly sexualized on National TV nowadays. And of course in terms of Clay... the irony is that people are now still offended by his work, but the offense has changed. It ain't his naughty language and overt mentions of sexual themes, but rather his blatant casual misogyny and treatment of women that people are offended by.Hold on a minute there. That label was enough for some pretty big outlets like Walmart to refuse to stock the material - and that most likely did affect potential sales. Same with NC-17 ratings for movies because big rental places like Blockbuster would refuse to carry them. Warning labels and ratings may seem pretty small potatoes, but they can have significant effects thanks to the nature of the marketplace in which they appear.
So no... if there was any "slippery slope" in relation to the Parental Advisory - Explicit Lyrics tag, it was purely economic in nature, not social. If anyone's intentions in making a product were held back due to the tag... it's because they were afraid of making less money off of it, not because they were now no longer allowed to make it in the first place.