I have a hard time to find cases when it's true in the context of media content.

Here is them arguing against retroactively applying a 70 year old copyright term in Canada to works published before 1978:

https://ised-isde.canada.ca/site/strategic-policy-sector/sit...

> For instance, if an author created a work at 30 -- the average age for a first childbirth in Canada -- and died at the average age of 82, with a copyright term of life of the author plus 50 years, and if the average of 25 years for a generation, we are into the fifth generation after creation of the work. Adding on another 20 years only compounds the capacity of heirs of authors to leverage extended copyright to prevent Canadians from accessing valuable cultural (and by that time historical) works. We have seen numerous examples of distantly removed heirs leveraging old copyright to prevent commentators from quoting extensively from well established works, or preventing historical pictures, news-clipping and other primary sources from being used without payment.

And indeed, it was implemented that way: https://en.wikipedia.org/wiki/Copyright_law_of_Canada#Extens...