There seems a measure of consensus that across-the-board big increases in time & standards (e.g.: knowledge/skill/performance mastery) would lead to a substantial decline in the # of people entering the hobby.
But of those who did, there would be a substantially higher retention of active, involved divers (
the ones who profit dive centers, but less so, agencies).
Most agencies profit from courses only - not fun diving or equipment sales. So the training model reflects that. Diver retention, beyond 'continued education', is not a consideration for agencies.
Most agencies would be happiest if masses of divers to simply progressed immediately from cheap, easy course to cheap, easy course, with no experience diving between... on a card-collecting spree.... led to believe that the number of cards they possessed in some way reflected actual competency as a diver...
Oh wait..... isn't that kinda what happens mostly nowadays?

Funny that....
Even if these courses cost the student more money, they'd also cost the instructor more time & effort.
I've never seen an argument that instructors want to make
less effort, or devote
less time to training.
The argument for shorter courses only stems from the desire to profit from student turn-over. A situation forced on instructors by the agency driven training model...
A number of instructors are 'dual vocation' and some have families, so taking up more of their time is a cost, too.
Dual vocation/Part-Time instructors is actually quite a tiny minority.... when considered globally. It happens in countries/regions that don't have thriving dive industries and masses of students. More full-time instructors in Mexico than Florida. More in Florida than Connecticut...etc
Also.... how many of those instructors would
choose to be full-time.... if the training model were re-shaped to offer them a living salary, rather than being at the bottom of a cost-cutting pyramid, for the sake of agency profitability.
How many GUE Fundamentals instructors drive Beamers?
Have you seen the cost of their gear?!?
But it seems a GUE instructor can afford the expensive stuff.. tech scooters, gasses, expeditions etc.... that they want/need. Most other instructors couldn't.... not from their salaries.
that there'd be a mass migration of these guys into the longer, more demanding and lucrative technical diving teaching market...if teaching tec. is lucrative. Is it?
That's exactly what we're seeing now....
Some agencies are creating sausage-factory tech instructors with that precise goal. The problem is that it then saturates the instructional market with under-experienced and grossly under-skilled tech instructors who did some pathetic zero-to-hero tech instructor program only because tech seemed lucrative to them.... a desperate solution to boost their miserly income and the unsatisfying instructional experience they get from teaching cheap, easy and non-productive courses to the masses.
What then happens, of course, is that these zero-to-heros then follow the same mindset as they had before..... unable to compete with experienced, skillful technical instructors of repute..... they start playing the 'price-cutting' game.
Then lo and behold....the same cankerous disease has spread to the tech diving community.
Tech diving is become cheap, quick and easy. Trust me on that....