I'm embarrassed to admit I fell asleep halfway through watching the film on Netflix.
I really enjoyed the first half, but after awhile, all those industrials began to sound the same to me. And as a previous poster noted, the film is more about the collector than it is about industrials per se.
But I do remember how much actors coveted those jobs back in the 1970s: short commitment, better than average pay, nice hotel rooms, congenial rehearsals, etc.