Yeah but Microsoft Office had a clear attack vector: it cost a significant amount of money and you could "beat" it for some (but not nearly all) people by being "good enough" and free.
Google Docs is free (yeah, you're "Google's product" yadda, yadda, but hardly anyone cares about that, they just know they aren't paying for it) which makes it much harder to attack unless your product is substantially and demonstrably better than it in at least some very important areas.
