I also do think current copyright terms are too long.
The general copyright term changed with each revision of the law.
Congress has voted to extend the current copyright term by 20 years.
In 1955, a revision of the 1922 law extended the copyright term from 30 to 50 years.
But if the bill also had a section on copyright terms that all of Hollywood was pushing for, his calculation might be different.
Domestic works at the same time enjoyed a copyright term of 70 years after the authors death in Germany.
Also, the work remains under copyright in some other countries where copyright terms are longer.
In 2004, this copyright term was extended to 70 years for all works still copyrighted.
Traditional educational materials, such as textbooks, are protected under conventional copyright terms.
Many countries have extended the length of their copyright terms (sometimes retroactively).