The new Nokia is a company that wants to sell you a mobile device that you'll use to purchase lots of music and other forthcoming content (N-Gage games) and lock you into their portals and services (navigation subscriptions). The device is only a means to an end, and giving customers choices by making the devices open limits Nokia's future revenue.
This apply to practically all available today pieces of code. You never know where submarine patent lies. And this is THE argument against software patents.