They try to keep a balance by mentioning at least one game from the popular developers.
Though there were some games that comblined both RPG and pnc elements
Some of the more ground breaking games back then were:
Personal Nightmare (one of the pioneers of horror adventure games, from the developers of the Elvira and Waxworks games, who feel more like an RPG though)
Normality (unique first person adventure game by Gremlin Interactive)
Bad Mojo (top down adventure game with photorealistic static graphics and amazing effects and soundtrack where you only use arrow keys to control a roach)
Dark Eye (first person adventure game with stop motion puppets, based on E.A Poe)
Shadow of the Comet (one of the best pnc adventure games, capturing perfectly Lovecraft's settings, much better than Dark Corners of the Earth)