What do you say?

I was at a convention this weekend, it wasn't a writing con but it was a place where a number of writers and aspiring writers were in the crowds. Naturally the conversations turned to writing and publishing a few times. Most of the people I spoke with were great. There were a few pros and mostly people who researched and knew about the industry. Unfortunately that left a gentleman who was clueless to an extreme. I endured a long rambling diatribe about his work and the state of publishing as a whole. I think that state might surprise people, evidently books don't get published anymore. Self publishing is the new only way! After all he'd sold ten copies of his book just last year. After the third attempt to interject sanity into the conversation I slide away and hid from him the rest of the convention. He wasn't going to listen to me. But what do you say to that kind of delusion?