First, Wittgenstein didn't record very many works.  Second, those he
did were not very well performed IMHO.  I have ONE CD recording of
Wittgenstein, and based only on his performance of the Ravel left hand
concerto with Bruno Walter (no less!, as conductor), therein lies reason
enough to leave off of the list of a multitude of much more deserving
artists already left off of the "Great (?!?) Pianists of the 20th Century"
venture.  Where (again, here I go) is Annie Fischer? or Leonard Bernstein?
or Lazar Berman, or,.......

JPrevite