Are they frightened to innovate?
Look at it this way: if they wanted to introduce new IP on the same level (budget, production value, potentially long lasting impact), they'd have another huge risk on their hands. They're taking a lot of risks with the hardware and they seem to try and support themselves by sticking to their established properties to carry them through it and sprinkling a little new stuff in there occasionally (like it or not, the Wii [blank] stuff was a new franchise for them). They're somewhat forced to play it safe with new IP and innovate within what they have. On the surface that may look stale but the end products are still varied and fresh.
The reason you see Sony go all out on new IP all over the place is that they never had strong franchises to begin with so they have nothing to lose in that regard. They don't have a core internal software studio that is involved in how the hardware turns out, for example. They have their Japan Studio and some other developers that they own but that's it. Their first party identity is that they have various experiments of stuff you've never heard or seen before and they try and see what sticks.