I'm not sure whether you're saying that there weren't google ads in the old iOS maps, but I'm fairly sure I saw an ad there when I did a search for Pizza Hut a week ago in SF.
There were. I think they called them "Sponsored" or something. It really annoyed me because if I'd search for something common like "Home Depot" it would give me random pins at places that were definitely not Home Depot but rather sponsored businesses.