I agree fewer writing jobs. The technology though if used most naturally will increase efficiency resulting in a higher quality of average professional writer. The human written writing will come from the very best writers there are. And the rest will be individualized and sovereign self-driven -- AI replacing writers wherever the end user has the tool available to write themselves whatever they want to read. That is not to deny lamentable adaptations necessary to prepare for the changes.

The greatest benefit though is realignment toward undistorted incentive (again, assuming used naturally). Appreciation of human created writing will come from a place of distinguishing it from what cannot be done without the human present who did such a thing.