What do creators do when those billion-dollar corporations have no risk from selling their art, which has an opportunity cost to make, without permission or compensation? It may cost little or nothing to reproduce, but it's not free to create. Control over reproduction makes the creation viable. Otherwise, they have to spend finite time and energy on other things to survive.
I would be willing to accept a legal regime that grants creators "protections" in exchange for the works reverting to the public domain in a reasonable period of time. Copyright is a social contract and, at the present, the consideration given to the public is too little. It's not enough for me to license works I create myself permissively to satisfy me. I want the playing-field leveled for everyone.
I try to live this opinion, personally, by paying for as much "media" as I can created by those who utilize patronage models or who license their work less restrictively than copyright permits. I find that I can't discuss popular music, movies, televison, and many books with other people but I'm not particularly sad that I can't. I don't willfully infringe copyright-- I just choose to ignore as many of the things that aren't permissively licensed as I can.
He wrote a good book, The Public Domain: Enclosing the Commons of the Mind (2008), which makes the case for radically shorter copyright terms.
This provides an interesting insight in an a simple quantifiable way that provides some interesting information.