Actually the 'Old School Mentality' has changed immensely in this particular sport .We have come light years in training techniques and sequencing particular sub skills. Results are readily apparent, learning more effective and since now this stuff is in printed and video form(something we never had), it's available to people in general. The old way would have been transferred by word of mouth or mentoring.
Rex Carr is responsible for the change and implementation of the e collar which has changed training .
By the way I don't think field trial trainers are 'gods' at all. They however, have been walking the walk and have an experiental base that is fairly broad in nature. Try training a 7 week old puppy for 8-10 yrs, competing and hunting over them only to start over once again will yield that kind of experience which is real and tangible.