As you correctly observe in your article, the typical response to a long bull market and insane valuations is for Joe Average to chant “it’s different this time” and then provide specious arguments to support the claim. The only thing that is unknown about a bubble is the precise day on which it will pop. Until that day, Joe Average will continue to believe that “it’s different this time” and nothing anyone can say, no data anyone can assemble, will convince them otherwise. Which is precisely why bubbles form every 10 years or so and then pop suddenly, catching all the Joe Averages out there totally by surprise.