You love short-term ergodicity in which you can do policy. Your critique of bubbles is all in terms of the long run, what is going to happen in some infinite horizon. Bubble players figure they are smarter than others and will know when to get out. On an earlier thread it was pointed out to you how a rational agent can enter a bubble which will end in finite time. No, although the early participants who get out sufficiently soon may be.
Bubbles exist and they are irrational.
Thanks for the thoughtful and stimulating piece. J. Barkley Rosser.