G may need publishers but they may not necessarily need me.
Quite true. And I would add that while G needs publishers, G does not need Adsense. It is a money making endeavor for G, but so is Adwords without Adsense. Adsense expands the advertising universe for advertisers, but if certain publisher site were to become too much of a headache for Adsense to police, then, yes, I could see a purge of those sites.