One philosophical justification for copyright is that it encourages creators to produce and eventually share creative works. But the law doesn't ask whether a work provides public value before granting copyright.
You are undermining the argument by including your faulty understanding of law and missing the bigger point. I am not saying copyright and trade secrets are treated the same in terms of protection by law, I am saying they should be. Because as a writer, I do not want to give my life's work away and let people do whatever they want with it. I want it to stay in my family and I should have the legal right to do it. If that means registering a company and using other laws to protect my work, so be it, but it is not meant to be given away for "public good" in my opinion just because its a work of art.