Fact is that over the years a great many vintage aircraft have crashed or had significant incidents at public air displays. Fortunately, changes in display profiles have lessened the chances of such incidents causing death or injury to the public though of course the effect of witnessing a fatal accident at such an event is a heavy one indeed. Public enthusiasm for such events does however seem undiminished.
I have wondered upon occasion whether one of the reasons for some of the accidents is that pilots are actually perfroming manoevres at low level for which the aircraft was not actually designed - in other words, what a pilot may get away with at higher altitudes in combat situations leaves almost no room for error at display heights. There is no doubt that both the public and the display 'circus' no longer wish to simply get these old aircraft in to the sky and display them in quite the same rather more sedate manner they may have done some years ago.
Sadly such accidents will probably continue.