Whither The 7th Guest-Style Puzzle Adventure?

Deunan writes "While poking around on the Internet, I discovered a DirectX front end for the classic The 7th Guest CD-ROM puzzle adventure. After some further searching, I stumbled across a more recent pitch for 7th Guest III: The Collector [apparently the game was in development in 2002/3, and there's an interview with designer Rob Landeros about it, but it seems to be stalled.] I was wondering what killed interest in it - are 'thinking' games just not popular anymore?"