I agree with the summary of the situation in your first paragraph.
Your second paragraph about sound mimickry, as far as I’m aware, is not accurate. Musicians have been ordered to pay for much less than rote mimickry, even simple things like using the same melody or beat as a backing track have been ruled as infringement. In the US, at least.
And I agree with the 3rd paragraph.
So I believe my original question still stands: should an artificial brain be required to pay licensing fees for everything it sees?