Remember when consumers could expect to play the exact same game as their buddy for the exact same price? Good, now forget that. As we established, this is a business. And since gamers still seem eager to spend money (points, credits, virtual funny money) on window dressing, it's our responsibility to keep those virtual shops stocked.
Here's where you can get creative. For starters, multiplayer games are microtransaction hotspots. Gamers like feeling like special little snowflakes, and they don't like working for in-game rewards like their parents did in the 1980s (got I feel old). Give 'em special colors for their weapons and let them buy their way up the online food chain. If you're making a solo game, put out something cool like a flaming sword or a silly costume. Screw it, let's get R&D in here and install debit machines in every consoles so they can just buy their way to the end of the game. After all, today it's all about collecting trophies, comparing e-peens, and make believe ranks. If you think about it, we're really doing them a favor.