I agree with the assessment that pure writing (by a human) is over. Content is going to matter a lot more.
It's going to be tough for fiction authors to break through. Sadly, I don't think the average consumer has sufficiently good taste to tell when something is genuinely novel. People often prefer the carefully formulated familiar garbage over the creative gems; this was true before AI and, IMO, will continue to be true after AI. This is not just about writing, it's about art in general.
There will be a subset of people who can see through the form and see substance and those will be able to identify non-AI work but they will continue to be a minority. The masses will happily consume the slop. The masses have poor taste and they're more interested in "comfort food" ideas than actually novel ideas. Novelty just doesn't do it for them. Most people are not curious, new ideas don't interest them. These people will live and breathe AI slop and they will feel uncomfortable if presented with new material, even if wrapped in a layer of AI (e.g. human-written core ideas, rewritten by AI).
I feel like that about most books, music and pop culture in general; it was slop and it will continue to be slop... It was the same basic ideas about elves, dragons, wizards, orcs, kings, queens, etc... Just reorganized with different wording.
Most people don't understand the difference between pure AI-generated content (seeded by a small human input) and human-generated content which was rewritten by AI (seeded by a large human input) because most people don't care about and never cared about substance. Their entire lives may be about form over substance.
What is the difference between writing and content?
I would guess he's looking to compare the equivalent of fast-food to fine-dining or nutritious eating.