That's because it's Google PR (http://www.paulgraham.com/submarine.html). Nuance Communications[1] (who makes Dragon and N other speech rec systems), is really the leader in this space. They've done server-based recognition solutions ~forever, and is the solution Siri uses for their app, for example.
[1] Note: this is not the same as the Nuance Mike Cohen started, but a conglomeration of speech companies purchased over the the years which inherited the name.
Yeah, but... i've tried Google Voice Search and it works incredibly well; whereas Dragon on the iPad did not work well enough to actually use for its intended purpose (although it was fairly impressive - i had low expectations).
[1] Note: this is not the same as the Nuance Mike Cohen started, but a conglomeration of speech companies purchased over the the years which inherited the name.
EDIT: Added some more detail