When you look at it, Google probably already has. 20% time is practically gone, Reader gone, iGoogle going, etc. All the various little projects that may not have had huge numbers of users, but still indicated that Google was a fast moving, innovative company are disappearing.
It may take a few years for people to realise they are a lumbering giant in decline now, but the seeds are already planted, maybe even full grown...
If history serves as an indicator, I would say the chances of that happening are relatively high.