It's simpler than everyone makes it out to be. Here let me explain. When a huge game is about to release... what does that huge game get? Large advertising and marketing. When this happens the platforms are required to be shown and even more so when exclusive. Basically when a huge game releases you get double the advertising which gets more people aware of the brand.
The other easy concept is you have more people in the stores buying the game haha. The more people there the better chance they have of buying the console then if they aren't there. And then of course people specifically buying a console for a game... however this is a much smaller percentage aside from Japan. Otherwise it's really just as simple as getting more advertising for the console and more people in the stores.
