Most of the examples of Google closed apps that are not part of the AOSP release are in fact apps that are based off of Google data-center services. Would it really help Samsung if the source to the Gmail app was open? Since Google controls the server side, and the client-server protocol, it limits the amount of innovation they can do. The web equivalent would be like claiming that Chrome OS isn't open because the so…
And, in fact, the same author made the exact same point about Google Play Services being a big tool Google is using to get past OS version fragmentation about a month-and-a-half ago: http://arstechnica.com/gadgets/2013/09/balky-carriers-and-sl...
"Not having to package everything into a major OS update means Google can get features out to more users much faster and more frequently than before. ... This should all lead to a more unified, less fragmented, healthier Android ecosystem."