I don't know enough about how the patent game is played. But I'd imagine it could play out similar to this:

- Apple is developing a new product that needs a few patents from Nokia.
- They try to negotiate for the patent licensing fees, but Nokia puts an unreasonably high asking price for strategic reasons (and it's their right to put whatever asking price they want for it).
- Apple decides that settling this in court may still be cheaper than Nokia's asking price, and they don't mind the public exposure.
- Game on!

These companies have homongous legal department and their moves are all dictated by dollar and cents. These things are almost always calculated moves for them.