Google scares rivals, but why?

Google scares rivals, but why? Is it because So Much Fanfare, So Few Hits?

Despite its unquestioned dominance in the field of online search and search engine advertising, Google's forays into other Web sectors have not produced a long list of market leaders.

Though its maps and online e-mail offerings are widely used, they are still outmatched by rivals in terms of usage. Other niche offerings like its finance site and blog search are less popular.