Well, I have been a adsense publisher for over 5 years now and they are pretty clear about their commission rates they give us 68% for content ads - https://support.google.com/adsense/answer/180195?hl=en (earlier it was 70% i think )
and to me it's not unfair as even if someone was to make such a OS system , he still has to manage server cost/support/advertiser acquisition/marketing cost etc. & so wont be able to pay as good as adsense also the ads initially wont be that diverse & so ads might not be in context or even blank spaces , kind of chicken and egg problem !
and to me it's not unfair as even if someone was to make such a OS system , he still has to manage server cost/support/advertiser acquisition/marketing cost etc. & so wont be able to pay as good as adsense also the ads initially wont be that diverse & so ads might not be in context or even blank spaces , kind of chicken and egg problem !