I do not tend to believe that the authorship was far from ideal for Google. Reading such claims or arguments clearly tell me that those persons could only scratch the surface of the intent and the cause of Googles action.
I do not deny that Google may have dropped the project now because they did not want to invest any further. But why? They fail? I do not think so. I believe they gathered the data/information or whatever else they needed to be able to feed their machine learning technologies and to be able move on and grow independently without our help, like the rich snippets markup or profile pics in the search results.
I see the authorship story like every other algorithm. Once Google sees that an algorithm is mature and stable enough, they push it into the everflux and discussions get buried, until someone opens the box and start bitching about a drop in his rankings or receives a manual action notification.
Lets take for example Panda. I feel it is almost there where Google will stop announcing updates of different versions. When that happens, it should tell us that it is then mature/stable/safe, but not dead! The same shall follow with other algos like Penguin, EMD, PMD, Emmanuel, Top Heavy, etc.
Unfortunately I already see around how several people picked up this authorship story and are trying again based on delusional based studies and statistics to show off and raise another wave of misconceptions leading to another misleading bomb, but which will not last long anyway, because I am pretty sure AgentRank will be the next balloon party, if Google does not come up soon with a new animal.
So to keep this short, which is that person with the required resources outside of Google who can tell what was behind that plan and if they achieved what they wanted, and if they had benefits or losses? In my opinion such illusions give another boost to the bad reputation of the SEO industry. But why care? There are new definitions found with the intention to hide the forest behind the trees which I explain here http://www.searcheditors.com/marketing-hide-forest-trees/
So who can bet on a claim that Google had a loss or fail on their experiment?
Maybe because I am an addicted semantic search professional I see these things from a different angle or perspective?