The reluctant vampire in film can be traced back to Gloria Holden in Dracula's Daughter - 30 years before Dark Shadows ever appeared. The only way that Barnabas is responsible for the "ruination" of vampires is because he was so good at self-loathing. Dark Shadows popularized the reluctant vampire because it told the tale in such a fantastic way, yes. But, Barnabas can't be blamed for "ruining" vampires. According to the author, Bela Lugosi would bear a lot of blame because he was suave, sophisticated, and attractive. And I have never heard anyone say that Lugosi caused the ruination of the vampire. Both Lugosi and Frid brought new life to the vampire character. Without them, the author probably wouldn't even be thinking of vampires as much of anything at this juncture in history. In fact, he'd be writing about zombies.