It's completely ass backwards and results in a total thwarting of creativity.
I compiled some research recently to assess creative work ethic amongst musical artists from the 60s to the present. It had nothing to do with copyright originally, but the data can easily be arranged to show some interesting things about what effect increasing copyright lengths may or may not have on creativity.
Using album lengths of studio albums for these artists I came up with a figure I called CPY, which just stands for content per year, which is measured in minutes. For this post, I took my data and divided the artists between 2 groups: Pre 1978 & Post 1978. Jan 1, 1978 is when the 1976 Copyright Act took effect BTW.
The Pre 1978 group had an average CPY of 42.55 minutes
The Post 1978 group had an average CPY of 30.6 minutes
This is about a 28.1% reduction in creative output after the copyright act took effect. Now, correlation does not imply causation, so it can't necessarily be said that this dramatic drop was caused by the copyright act. However, it can certainly be said that the copyright act definitely is NOT causing an increase in creative output. There is no evidence of such in the data whatsoever. In fact, creative output has held close to the margin of error from the 80s onward in my data.