What makes the Google threat particularly dangerous for Apple is that Google appears to be innovating at a much higher rate. Hardly a month goes by in which there is not an announcement from Google of one type of new product or another. Meanwhile, Apple remains hidden behind its curtain of secrecy.
If Google can overcome the difficulties of providing software across a variety of manufacturers, as they appear to be doing with Android, and if that software is as good as Apple’s, the reason for paying a premium for Apple products may disappear. That poses the greatest risk for Apple investors.