We learn that the text of the play is not the play, still less is the written and published text of the play anything like the theatrical experience, which will vary considerably with individual productions, each production being a complex vision worked up into performance by an individual director-artist in company with individual actor-artists.
E：I think “the text of the play is not the play” means that reading a play is very different from seeing it performed. The performance depends on the director and actors, so the written words alone don’t show the full experience.