[Ascovel]

Like Idrisguitar said most of these are Japanese and quite a few were created with handhelds in mind. So they not only offer different styles of play and storytelling, but also miss a lot of features the PC gamers take for granted. I'm not even sure all of these are true adventure games or more like evolution of the visual novel genre.

So in short there isn't any strong market established for games like that on the PC... Yet.

But look what's already happening - Telltale Games has been borrowing ideas from Layton and Heavy Rain for their newest games. Recettear - a Japanese "RPG item shop simulator" - has been ported to PC by an indie team and enjoyed a lot of sales. More and more titles like that will start to seep through. Especially anything that's attractive to the casual market.