The sad truth may be, that Zeppelin were not able to get much more pro-shot concerts on flim, than has already been released. It very well may have been their intention to film more in 1975, but that got cut short because of Robert's car accident. Then, in 1977, that tour got cut short due to Robert's son's tragic death. Then in 1980, their tour got cut short due to John Bonham's untimely death.
So there very well may have been plans to film the band professionally in all of those tours, but fate would not, and did not allow it.
One would ask, what was Fate afraid of the world seeing ???
The Best Live Rock'n'Roll band, ever.