Google Maps is also integrated into the Google search. Any time it detects that you've entered a mappable location it provides a Google Maps link. If this feature were removed by, say, a lawsuit by Mapquest I think that Google would become less effective, and everyone would suffer as a result.

That's just my personal opinion, however. I had (and still have) no objection to Microsoft bundling a web browser and media player in Windows, and yet they've been hit by antitrust charges.