Why assume there would be less overhead without the ads?
With ads, there is also probably less friction visiting unknown sites; clicking to a site with too many ads and then just closing it is probably a better experience than knowing you blew $0.05 on crap content (I'm not saying getting frustrated about $0.05 makes sense, I'm saying it will probably happen).
You and dragonwriter are missing my point about innovation, and also greatly underestimate the overhead cost of the advertising-publisher industrial complex.
With ads, there is also probably less friction visiting unknown sites; clicking to a site with too many ads and then just closing it is probably a better experience than knowing you blew $0.05 on crap content (I'm not saying getting frustrated about $0.05 makes sense, I'm saying it will probably happen).