Wiley I am guessing you have never been an instructor then. When I used to work there 5 years ago or so, for every one hour flight (which is what most of were paid by, whatever the rate was/flying hour) there was usually a 45-50min pre brief, a short debrief (often done walking back to the club so you could be ready to go with the next student who was waiting - longer on the whiteboard if required) then another 10 minutes at least doing an FPR. If it was a nav then the FPR could take 20-30 minutes depending on how the flight went. If it was getting close to a pre license add in another hour or 2 checking through all the paperwork, doing the summaries, checking the hours against the student's logbook etc etc etc.
I reckon it has gotten worse in the last 5 years too. So before being to critical of the "lazy arsed instructors" perhaps walk a mile in their shoes.
Luckily these days I just tell pilots where to go, but it would be a shame to see the club collapse, I did generally enjoy my time working and flying there.