I don't think that's correct. Apple makes the application, not Google. It's possible, but it seems unlikely that there's a clause in their contract that says, "we'll give you map tiles, you also have to show these sponsored links."
I fully expect Google will ship their own mapping app for iOS, if they're ousted from Maps. Also, it's not like there isn't already competition – searching for "maps" on the App Store reveals a healthy collection of mapping apps, including MapQuest and Garmin.
A quick bit of Googling turned up the following confirmation that those ads are, in fact, sold by Google: http://thenextweb.com/apple/2012/01/06/hate-the-ads-in-the-i...
I fully expect Google will ship their own mapping app for iOS, if they're ousted from Maps. Also, it's not like there isn't already competition – searching for "maps" on the App Store reveals a healthy collection of mapping apps, including MapQuest and Garmin.