A rapid rise is not a prerequisite for sharp declines. The market was up modestly the twelve months preceding the almost 50% drop in 1973-1974.
True, but I just shrug when I hear "bubble" and then look at the SP500 the last 3 years. But you're right, we can always goto zero in the indexes with the proper outside macro events (earnings, inflation, interest rates, World War III, pandemic desease etc.). But before that is on the radar screen I wouldn't fight this market.