I'd be interested to have Terry or Burt, or other long time instructors
weigh in on your opinions.
Having done this many times, I can not imagine how you can properly
prepare a candidate for instructing( notice I did not say passing the
practical test) in the time you describe.
The difference, in my view, is the experience needed to evaluate the
candidate and tailor the training program to the candidate's situation.

As to the attractivness of the instructing situation, those that do it
get rewards that might mean little to some folks but are big to some of
us.
Examples- the look on a 14 year olds face after first solo, the call
that your student just won his or her first race, the call that "I just
made captain at my airline, I just got my CFIG, I just got into the Air
Force, I just did my Silver, Gold, Diamond.
I thought it was abig deal 32 years ago and still think it is today.
Sorry to be excessively self congratulatory, intent was to provide
background of experience to support my opinions.
UH