"Instead, Google+ is a social layer that has always been intended to sit on top of the company’s flagship product: search." Flash back to an anonymous Stanford office, circa 1996, where two ambitious graduate students are sitting in front of a pile of lego servers: Larry: "Hey Sergey...you know what the world needs? A place where people can share cat photos with their friends." Sergey: "Oh, Larry...how many times hav…
It seems clear to me that the author meant "always" wrt the inception of G+, not the inception of search. So your snark, while amusing, is misplaced.
"Sure, Google hopes to build a social network that competes with Facebook, Twitter and other social services, but that is not the main reason the company has put so many resources behind Google+. Instead, Google+ is a social layer that has always been intended to sit on top of the company’s flagship product: search."
What? "Google+ is a social layer that has always been intended to sit on top of the company's flagship product: search" just exactly as long as they decided to "build a social network that competes with Facebook, Twitter and other social services". He is somehow trying to sleight-of-hand away the causal relationship here. If Google+ fails to rival Facebook and Twitter as a social network, it might still turn out ok somehow, but it will doubtlessly be considered a failure internally and externally.