L’, you know , I wonder about that “guys in the trade” business.... Most of the guys in the trade around here want a product they can apply quickly, easily, and with a minimum of work needed after... and have panned some good quality products as being too labor intensive , taking too much time for them to fool with, or in their terms “no good” ... That’s how they make money , rolling one job to the next , the less time spent on each job , the more money they make .... just the reverse of we “hobbyists”

As far as tradesmen knowing of lasting results, I kinda’ doubt it , they’re long gone before any problems show up , and you know they Never do this to their own stuff ...
