First Air Supply were great! Or more accurately their two songs written by Jim Steinmann were great.
Second I find Gygax a more challenging case than Lovecraft. Mostly because as I said in the other thread one of the things D&D is is a work of moral philosophy. I believe more people have spent more time and effort engaging with nine point alignment than they have Socrates, Descartes, Nietzsche, and Ayn Rand combined. And you spend more time being with and absorbing and embodying the colonist settlers of Keep on the Borderlands than anyone ever does when they read about Herbert West, reanimator.
And from what I can tell Gygax's understanding of good, especially Lawful Good ... isn't. His law Vs chaos is a Fantasy Western with lawful folks back East, Chaotic/Evil indigenous inhabitants and where the settler's are presented as morally right. And his Paladins bring it all together with even more problems of their own.
And in terms of works of moral philosophy with actual influence over people D&D is almost certainly high up in the second tier of recent centuries (it's no Communist Manifesto, Little Red Book, or even Wealth of Nations but probably beats any work by any primary philosopher)