The dotcom bubble was the "new economy", the old economy had changed forever and was dead. No one thought it was a bubble. Even when the bubble popped it took until 9/11 to wake us up from the mass hysteria.
I can't think of another "bubble" that practically everyone thinks we are in a bubble. To the point that I think many would find it irrational to believe we are not in a bubble. That is not what bubble is. A bubble is the madness of crowds, not the wisdom of crowds and the crowd certainly believes we are in a bubble.