I think maybe we can introduce a law saying that any X% portion of poetry or book (e.g. 20% for poetry and maybe 200 words for a book) is in the public domain immediately following its publication IN ONE QUOTE.
But it probably introduces other complexities such as how to define one quote. Ah, wish we could advance from rule of lawyers to something better. What is it? I have no idea.
I took an IP law class in grad school. I asked the professor a question about making a more clear rule about how much is use of a copyrighted work is fair use or something along those lines. (I think I had some vague idea about using information theory to quantify it though I didn't say that.) The response was some argument against "bright-line rules" [1] like what I was proposing. I personally can see how bright-line rules can be bad in some contexts, but I don't think copyright is one of them. Legal clarity would be very helpful here in my view.
But it probably introduces other complexities such as how to define one quote. Ah, wish we could advance from rule of lawyers to something better. What is it? I have no idea.