Besides the obvious reasons, here's an ancedote: I know somebody who bought a PS4, but has not gotten any retail games for it. It's not that they've been buying digital copies; they literally only bought the hardware. They just wanted to have a PS4 around for when games like Infamous come out.
Looking at the software ratio of about 2 games for every unit of hardware, it appears that people simply don't want that many games for their new systems yet. And of course, having lots of less notable games at launch means the sales are more spread out.
So far, it simply looks like the new consoles are boxes for existing shooters released beforehand on weaker systems.







