@repulsive44552: To a degree you were always on-rails in all of the Metroid Prime games in a way that you couldn't reach some things like munitions' capacity increase before you killed a boss or reached a certain point in the game and the bosses themselves were unreachable until a certain progress was made.

What I meant with my previous comment, was that games like Call of Duty and Metroid Prime aren't of the same genre. There is a very distinct borderline between them and they most probably won't be enjoyed by the same set of people and thus we cannot talk about them as one and the same.

From this difference arises different approach in level design. Most modern Call of Duty and Battlefield games are mostly there for the simple sake of just being there to be shown on E3, GameExpo etc,, whereas Metroid Prime was all about single player experience which was worked on more thoroughly and carefully, including the placement and number of hostiles which were there to increase the difficulty of stage.

@repulsive44552: Have you ever actually played Spear of Destiny or any other early id or 3d Realms' FPS?

What you actually wanted to ask is, why aren't there more action-adventure first-person shooters nowadays. The answer is, there are. A lot of good examples like Dishonored, Bioshock, Far Cry, Fallout and Deus Ex have been mentioned. A lot more are on their way, most prominent of them being Fallout 4.