There are a lot of negative consequences:

1. Entire classes of skilled jobs are eliminated, only the most elite writers and artists can make money

2. Value for story creation gets concentrated in the few companies that own and operate the best LLM's and best stable diffusion models

3. Society becomes more fragmented because we are all watching different content

These are just a few I'm able to think of in 2 minutes.

It's a common mistake to assume all technological progress is an unadulterated good. Just look at all the unanticipated negatives that came out of the computer revolution, like every technological revolution before it.