In 1974, the show had just been cancelled and was never really a big hit in the ratings in primetime. It never made the top ten. It was up against Sanford and Son. I think at the time all the producers cared about was making money--not preserving the show unfortunately. They just wanted to...
They didn't film in 16mm. They filmed in 35mm, but some episodes were edited for syndication back in 1970s, so they replaced the missing segments with 16mm copies for the DVDs because they couldn't find them in 35mm.