OT I know, but I had to chime in. There is hope. With AdSense's Value Pricing of ads, I think relevant quality content will earn more as advertisers pay more for clicks on sites they value. Those sites where a click leads to a higher percentage of sales have more value to an advertiser. I think a "get me out of here this is dross" click is less likely to earn and there for pay as well. This video is more useful than the commentary, IMO. I know there are always other factors but the sales is a way of measuring the value to the advertiser, if nothing else.
http://www.seroundtable.com/adsense-pricing-reduction-14657.html