Still, the creative-writing program, unsystematic or even anti-system
as it might believe itself to be, is a system. People go in at one end
and they come out the other, bearing (like the Scarecrow) a piece of
paper with a Latin inscription, but also bearing (unlike the Scarecrow)
the impress of an institutional experience. The nature of that
experience mutates as the folk wisdom of the workshop mutates–from
“Show, don’t tell,” which was the mantra in the nineteen-forties and
fifties, to the effectively opposite mantra “Find your voice,” which
took over in the nineteen-sixties and seventies. McGurl suggests that
these mantras encode shifting patterns of cultural assumptions–about
identity, about work, about gender and class, and, of course, about
what counts as good writing–and that they have had a big effect on the
stories and novels that American writers have produced. “The rise of
the creative-writing program,” he says, “stands as the most important
event in postwar American literary history.” — Louis Menand, The New Yorker

Read to the end — Menand is being professionally skeptical throughout the essay, but he admits in the end that learning to write poems is a process that brings its own benefits, whether or not they include publishing poetry.