They could, but they would have to change their TOS, which business customers would have to agree to. Most of these customers would not, thus destroying this p

They could, but they would have to change their TOS, which business customers would have to agree to. Most of these customers would not, thus destroying this portion of Google's business, so they would never do that. Ads are not a part of Google's Enterprise business model. I don't know how to state this more clearly.