VM
There's stuff from before the mid-70s that was kept, of course, just not as much as afterwards when things started to be properly archived.
One thing I don't understand is why no one thought to keep a copy of what coincidentally began 50 years ago today, the Apollo 11 moon landing coverage. I know a lot of recordings were wiped because it was thought they would be of no value after their first or second broadcast (no home video and no UK Gold at the time) but it seems like it would have been pretty clear even then that it would be an historic broadcast.
One thing I don't understand is why no one thought to keep a copy of what coincidentally began 50 years ago today, the Apollo 11 moon landing coverage. I know a lot of recordings were wiped because it was thought they would be of no value after their first or second broadcast (no home video and no UK Gold at the time) but it seems like it would have been pretty clear even then that it would be an historic broadcast.