I can remember watching a copy of Rex Carr and Dave Rorem vhs at the Manatoba Retriever club around 1995. It is my thought that this was the first commercially produced training video. A coupe years later TRT came out with Mike Lardy. Imo these tapes (later dvd format) increased our training knowledge 100 fold.
Now for the question, Why did they give away their magic for such a paltry gain in income?