Serkin sucks

Rudolf Serkin, piano and wind quintets of Mozart and Beethoven: goodness gracious, I had no idea that Mozart and Beethoven could be played this badly. I have certainly lived a sheltered life: I have not studied music and therefore have not had the opportunity to listen to beginners torture their instruments; and the wonder of air travel and internet shopping have insulated me against all performances save those deemed very best. I simply did not know what was possible. What is, indeed, the -- usual?!