I suppose good programmes from the school's point of view never die, even if they start looking dated.
You make a valid point. I was once discussing schools programmes with parents and we all agreed that some schools programmes stand the test of time better than others from the perspective of a learning resource. A programme from the 1980s about computers will probably be hopelessly outdated but a programme from the 1980s about the Battle of Hastings or chemical reactions could be just as usable today as when it was new - after factoring out the styling of the presenter's shirt!
State schools in England are only officially allowed to show programmes if they are up to date with the National Curriculum and sufficiently multicultural. The result of this is that state schools have disposed of the vast majority of older schools programmes they recorded over the years but some are still being used today in independent schools.
It was commonplace in the 1980s and 90s for people in Britain to record schools programmes then export the tapes to various developing countries for use in education there.