[Jensson]

But almost all ad money Google gets comes from their own services, so if they had the choice to open up to other ad providers or stop accepting other sites ads in the market they would just stop running ads on third party sites.

Likely the solution would be to spin out a separate service for third party ads and make the main network only run on Google services. But that wouldn't help ad websites in Australia at all. The end result would be that websites would probably have a harder time getting money from Google, which would be good for competing ad tech systems but it wouldn't make more money go to those sites.