Have you been to the internet?
In all seriousness, the cream will rise to the top. The mediocre “content” will get generated and we will get better at filtering it out which will decrease the value in generating mediocre content, etc etc. The tools being produced just further level the playing field for humanity and allow more people to get “in the arena” more easily.
Humans are still the final judge of the value being produced, and the world/internet will respond accordingly.
For a thought exercise, take your argument and apply it to the internet as a whole, from the perspective of a book or newspaper publisher in the 1990s.
High-quality content rarely rises to the top. The internet as of 2022 optimizes for mediocrity: the most popular content is the one which is best psychological manipulation using things like shock value and sexuality. Just take a look at Twitter, Facebook, or Reddit: it is extremely rare to see genuine masterpieces on there. Everything is just posted to farm as many shares and likes as possible.
If anything, this will result in the cream getting drowned in shit. Not to mention that artists do not get the space to develop from mediocre to excellent - as the mediocre market will have been replaced with practically free AI.