On the other hand, setting the value based on yearly sales is even less workable, at least for the open source community. The people making most of the money from Linux are the release publishers, not the copyright holder (Linus). Do we really want the paperwork nightmare that would result from trying to manage this?
My own feeling is that the best answer is also the simplest: Cut back the duration of copyright to a more reasonable time -- say, somewhere around 5 to 20 years. I would also, in the case of software, advocate putting the source code in escrow, to be released to the public at the end of the copyright period. There would, of course, be nothing preventing the author from improving the code in the meantime and acquiring new copyrights at any time, but the new copyright would only cover the changes, not the original unmodified code.
Intel CPUs are not defective, they just act that way. -- Henry Spencer