I think adventure games were doomed because their success depended on hardware restrictions limiting the competition. The main selling point of adventure games

I think adventure games were doomed because their success depended on hardware restrictions limiting the competition. The main selling point of adventure games was graphical spectacle. Adventure games had better graphics than any other genre because the lack of action meant they could show the most impressive static images. For the bulk of the audience, puzzles were secondary to this, serving mostly to ration out the graphical spectacle so the players felt they got value for money. Look at the success of Myst. I would be very surprised if more than 10% of people who bought it completed it. Myst simply looked better than any other game and that was enough for it to sell. Even King's Quest 1 was considered graphically impressive at the time; it was advertised as "3D" because the characters could be partly obscured by foreground objects and this was an important selling point. Once you could get the same kind of spectacle in action games, and I'd claim Half-Life as the first notable example, there was no longer any need for mass-market adventure games. EDIT: Thinking about it, Metal Gear Solid beat Half-Life to market, and that has the same kind of visual spectacle in an action game I'm talking about.