Train a model on a data set that has had all instances of small talk to close a conversation stripped out and see if the models evolve to add closing salutations.
This is not my area of expertise. Do these models have an explicit notion of the end of a conversation like they would the end of a text block? It seems like that’s a different scope that’s essentially controlled by the human they interact with.
They're trained to predict the next word, so yes. Now, imagine what is the most common follow-up to "Bye!".