Partially true.

If StackOverflow dies because nobody uses it anymore, the entirety of its knowledge is now only available through LLMs that trained on it.

If a blog dies out because the author gave up writing, the entirety of its knowledge is now only available through LLMs that trained on it.

If people stop writing books because they cant outcompete generated content, that knowledge is also lost to LLMs.

If people stop making art because they can't outcompete generated art, that is also lost to LLMs.

So yeah, they haven't directly taken anything away, but the consequences of what they are doing may still have that outcomes - and it does look like that's the version of reality we're about to get.