I think the point is there may come the times when there two frameworks that depends on different version of dependencies. It could be the Backbone-UI and something else.
It would be okay if the consumer code is dependent on all the libraries. But if one of your framework is dependent on certain version of library and another one depends on another version of the said library, that is disaster waiting to happen. It would be hard to upgrade one framework , hence making it hard to move forward since your code is all tangled to all the frameworks.