I thought that might be a mistake. But then it was said again in the article. It’s really not a lot - by our standards today. But then considered that, IDK, for 1969 this might be more then it seems.
Long lengths of film became physically unwieldy in the days before digital video.
(This is also why "footage" is called that.)
Used for cine, that same 100ft was good for about 1 minute of footage..
For widescreen optical compression was used to compress the frame horizontally.
It is unusual to have this much previously unreleased footage, from so long ago.
That sounds like an agonizingly dull job.
I read once that the job of listening to tapped phones was a soul-crushing experience, as you're forced to listen to the banality of other peoples' lives.
The home VCR didn't happen until the mid-70's for those willing to shell out some serious money. It wasn't until the 80's that it became a mass market item due to affordability which is why you can find so much more video preserved from the 80's and after uploaded to YouTube.
[1] It was expensive enough at the time that it was often recycled (recorded over) after whatever show it was for was aired rather than archived.
[2] Also expensive and is a write-once medium so used even more sparingly.