Wonder why your Adsense earning dropping inspite of full adsense optimization? well blame Google? or Bing?
Google is just doing the balancing to keep everyone happy, Suppose Google increases adword advertiser rates, advertisers start to switch to Bing, which is not good for anyone. Google wants nobody to leave their network
2.Suppose Google decreases adsense publishers earnings, can do till there is no major network competing anywhere close to its payout.So risk of publishers leaving is fairly low.
3.Suppose Google increases publishers sharing say from 68% to 78%, Can't do this because it effects the investors return and stock price heavily.
So Google is in fix, It can do nothing to increase your earning except few tips of optimization which can help a newbie not for old timers.
what can increase your payout?
Market forces, If Bing increases advertisers rate then Google can also increase your earning or else you are in a fix.
or
If Bing loses its market share can help us to make more money since advertisers have only one option that is Google.