7. Mass Appeal
With a huge chunk of the planet's population playing video games on some kind of device, from mobile phones to home consoles and PC's, it's obvious why developers would want an easier game. How would they appeal to the young sibling of yours, or my housewife mother? Easy: make a game they can both play, and that doesn't require much thought. While it's true that educational games, or games simply catered to a young audience exist, the difference between those and the point I'm making is the target audience. Nowadays, developers may pitch an adventure blockbuster to core gamers and families alike. For example, my father really wanted to play Fable, for the premise of it and the cool-looking action. Guess what? Fable III came out, and he managed to play it, even though he's more of a Gran Turismo/Tourist Trophy/Super Mario guy when it comes to gaming. And even then, he said the game was too easy and dumbed down compared to what he saw me do in Fable II (which he never managed to get into). This ties perfectly to the next reason on the list...
Example: Fable III