While I agree with the salient point in the article, I disagree with the emphasis on the size of the script. If using a framework reduces headaches and saves developer time, it will be significantly less expensive to use the framework than to roll and host your own solution. ALSO, there exist cheap/free CDNs that host many of these libraries:
backbone -- http://cdnjs.com/libraries/backbone.js/
rainbow -- http://cdnjs.com/libraries/rainbow/
socket.io -- http://cdnjs.com/libraries/socket.io/