A great read!
Maybe the dichotomy between a feature and a product does not apply in the case of bots in general and chat bots in particular. Is Dropbox about backing files or about making your digital world accessible across people and places?
The mission of an intelligent assistant is quite different. If the era of the GUI that has practically started in 1979 comes to an end in the following decade, and if the new paradigm will involve a non-UI, then the definitions of the feature and the product will have to be re-examined.
Again, if AI is the new UI, then although the companies will try to restrict bots into their proper walled gardens, one can assume that the bots will somehow find their way over these walls. Platforms will exist but the old notion of interoperability will surface again.