James Keller repeats the old story in the program booklet of the San Francisco Symphony:
Once, walking with the pianist-composer Johann Baptist Cramer, [B**th*v*n] heard an outdoor performance of the Mozart concerto. He stopped, called attention to a particularly beautiful motif, and exclaimed, with a mixture of admiration and despondency, “Cramer, Cramer! We shall never be able to do anything like that!”Many years ago my own first experience of the piece live was in a performance by the school orchestra at U.C. Berkeley under James Senturia: the soloist was, of all people, Ian Underwood, later of The Mothers of Invention. At the time he was a student at UC and a music assistant at radio KPFA, where I was then also on staff. He had prepared his own cadenzas for the concerto, and as I recall they were appropriate to Mozart's style while still probing and expressive of our own day; nothing academic at all about them.
Another time, at the Cabrillo Festival in August 1964, it was Ludwig Olshansky at the keyboard, and this was where I learned that it is in measure 329 (or thereabouts) that the greatest stress must be placed, on what seems an impossibly low note but is in fact only two octaves below middle C, a note that sounds and resounds and brooks no demurral. I don't recall whether it was Olshansky who did this, or Gerhard Samuel, who conducted; I only recall that it was the pivotal note of the movement, and has remained one of my favorite aural landmarks.