rsiano, you have to admit that engine technology has changed since 1967. We operate all of our aircraft with Derate/Assumed and in some cases such as the 787 our engine warranties are based on achieving an average thrust reduction of xx%.
We have never had an incident nor accident attributed to the use of Derate / Assumed thrust.
A pilot who consistently refused to use this procedure would be invited for coffee and dates with the fleet management
Mutt