There are many hyper-credentialized, gatekept systems but most of them don't share the feature of producing structurally worse outcomes as literary fiction. I believe this system is already selling the seeds of its own demise.

A small group of agents hold most of the power, and the system has confused power for taste. This has also, in my experience, led to the outlets that hold the most power using that power to push agendas instead of seeking out the best literature. I do not believe this can persist indefinitely.