Steiner, to my amazement, in an interview I just experienced, said that his father inculcated in him a desire that to teach was more important than to create.
Creators work their magic from thin air; they originate. They borrow, and are influenced, yes, but only from a long line of antecedent like-souled driven creators.
The teacher, critic, reviewer (Steiner, in the relevant irony) is entirely dependent upon the creator. An artist can teach. But without the artist, a teacher is out of a job.
Irving Layton reacted in similar fashion to Northrop Frye's contention than a critic was the parallel force to the creator, the synergistic necessity. The poet dismissed this as: "Fleas need dogs; but I've never known a dog who needed its fleas". Layton, angered at teachers' hubristic defense, compared their operation to that of "parasites".
Of course, Layton was, himself, a teacher, and many artists are also critics. But the hierarchical observance is important. I feel that Steiner (and others) inflate the role of the critic/teacher in order, by relentless attachment, to piggyback the Parnassian adventures of the creators they admire (or deride), and in doing so, acquiring a hoped-for reflected glory.
Critics are important; teachers are indispensible. But without creators, even the best teachers would be instructing their acolytes in the best way to hold a fork at the dinner table, or in the vagaries of deconstructionist relativist ambiguity in the third-removed footnoted transmissions of Derrida.