Z:gnu-www-ja-copyright-versus-community--29f5a8-A wave of this started in the/en

A wave of this started in the US in 1998. Copyright was extended by 20 years on both past and future works. I do not understand how they hope to convince the now dead or senile writers of the 20s and 30s to write more back then by extending copyright on their works now. If they have a time machine with which to inform them, they haven't used it. Our history books don't say that there was a burst of vigor in the arts in the 20s when all the artists found out that their copyrights would be extended in 1998.