That pretty much means that the biggest owner of patents for mobiles does not manufacture them anymore. Thus the mutually assured destruction does not hinder them anymore.
I'm not surprised if we'll see a bunch of patent lawsuits against everyone else except Microsoft within an year.
Microsoft buying Nokia is kind of the same as Google buying Motorola for 12 billion $ :
Nokia has 10k patents in the mobile phone world.
So a 10-year license to its patents has its importance