you think a downturn in sales in the mid / late 80s can be attributed to the satanic panic?
As far as I know it just made D&D popular by making people aware of it, I am not aware of any downstream consequences (apart of renaming devils and demons in 2e)
Definitely.
Obviously, there were fads in the 70s and 80s, and when the fad ended, so too did the boom times. I don't discount the extent to which the "fad ending" had a deleterious effect on D&D. Nor (if you've read
Game Wizards) should you discount other factors, like mismanagement.
Even so, the Satanic Panic led to a lot of issues. I think that people get confused because of the dates and impacts. The initial (Egbert) Satanic Panic led to a massive boom in sales and popularity. The later (Pulling) panic happened to coincide ... with the fall of D&D.
BADD wasn't formed until 1983, and it's success in the Christian conservative media really took hold in 1984, followed up with more appearances in mainstream media in 1984 and 1985 (60 Minutes). It was those appearances that coincided with the rapid decline of D&D as a mass-market phenomenon. Unlike the earlier Egbert controversy, this didn't drive sales, instead it forced distributions channels to stop offering D&D, forced clubs to close, and caused many people to stop playing.
We forget this today, but BADD succeeded in getting D&D pulled from some public schools and school districts- places that otherwise might have caused another generation of players to blossom (and purchase books). In other places, even when D&D wasn't banned outright, it was marginalized and the clubs that had been formed were disbanded under pressure. Major retailers that offered D&D pulled back or otherwise wouldn't offer it for sale- it went from being a mass market game with a "Red Box" available at the department store to something you would only find at a book store or a game store.
I would make a further (and more controversial) argument- that the internal codes and policies ... the
self-censorship within TSR starting toward the end of 1983, also caused a decline in sales. To the extent that good products sell better than bad products, I don't think it's particularly controversial to state that TSR was making better products (in terms of content) from 1977-1983, and then had a fallow period until the moral panic receded somewhat and we had the 2e product lines coming out in the 90s. I would say that this quality effected sales- while there are people that still love the rules and the direction of, say, the DSG or WSG, it's hard to say that people were
excited by those products.
Can I exactly quantify this effect? No. But it certainly didn't help.