Another model I've seen for copyright is that you declare a "buyout price" for the copyright, the price at which you will release the work into the public domai

Another model I've seen for copyright is that you declare a "buyout price" for the copyright, the price at which you will release the work into the public domain. You pay 1% of that price every year as a renewal fee, with a 10 year limit. Don't know if it would work but it's interesting.