That would have been a much bigger assault on openness, to be sure. But this is quite bad as well - it clearly shows that Google cares more about pushing Chrome itself than pushing the open, standards-based web. As the article says, when Microsoft's web demos are more standards-based than Google's, you know something is messed up.
Not so long ago I don't think Google would have done such a thing. Apparently though there are changes happening.
Locking other browsers out of gmail, gmaps, youtube, etc would be an assault on openness.