I also think that copyrights last much longer than they should. Their purpose should be to motivate creators to produce things that will eventually end up in the public domain. Do we really need life span plus 70 years to do that?

What about “work for hire”? Does creating for a corporation’s benefit motivate people to create more than they would if they had some particular fraction of the revenues from $MOVIE or $SONG for some period of time (such as three years) and then after that, it was public domain?