"In-game tutorials are both hugely important and difficult to pull off, and today's game-designers have gotten pretty clever about putting them together."

Disagree heavily. Many of the most complicated games from the past had no tutorials, but people were still able to figure them out. Figuring out was part of the fun in fact. Most people I know simply ignore tutorials.

And I can't blame them, because developers tend to be horrible at putting tutorials together. Most tutorials today start with the most basic things imaginable- moving your character and moving the camera. These things don't change from game to game. Only a very small number of modern games have tutorials worth playing.