CorvusCorax
'It's only a laugh, no harm done'
their owner is ignorable white noise which is the bread and butter of those kind of books and TV shows.
In that cynical vein, never actually finding a definite solution to certain problems means that the money keeps rolling in.
Some behaviours can be reversed in one session without too much fuss. Sometimes there is a deep rooted psychological issue going on which requires careful handling, sometimes the dog has never been taught to just quit it, as it's not in their best interests.
No need for an initial home consultation for a three figure sum, training plan, repeat follow up visits, etc etc.