If google bans legitimate publishers, then the advertisers move elsewhere.

Also, increased click fraud on tracking ads lowers their attractiveness, nudging ad revenue toward sites that serve display ads targeted to their content.

This helps funnel money to sites that produce high quality content and away from low quality sites that happen to attract users that view high quality content elsewhere.

and when networks have no publishers left, what do happen to them ?

> no publishers left

They become the publisher. In the grand scheme, this is a misguided effort that will further monopolize publishing.

So what will they publish then, fake news?