The only reason I think Google may avoid the sort of death described here is that it has financial momentum on its side. It seems to me that it is big enough (and ugly enough?!) to continue despite the challenges. It has the capacity to include social networking aspects in its searches, and already benefits from being able to crawl content provided by networks created under other platforms.

Twitter tends to be competing with it for my searches now, although only in those areas where my network is likely to have an interest. I am more likely to continue using Google (or other engines, depending on my whim) for areas outside my community's specific domain of interest.