Pool instruction is beyond adolescence by far.
I strongly disagree here. As Matt alluded to, there is a whole lot of bad instructors out there.
I'll use this basic comparison with a mature instruction industry in golf...
If you presented a collection of what I'd consider as BASIC concepts in motor-control, motor-learning, and biomechanics, to a 100 golf coaches, most would say 'of course' and acknowledge them as true. From what I've seen and the discussions I've participated in with some instructors, the majority of pool instructors just aren't at that level. The top guys are great and I will tip my hat to them as they know a whole lot and also know enough about not overloading students by actually divulging the minutia to them but say only enough to get the student to do and experience first-hand the concepts being applied. On the other end of the spectrum, where unfortunately the majority find themselves, many (most?) instructors are quite unaware.
Without actually diving into what these concepts are, here is what this knowledge gap ends up looking like in the respective industries.
In golf, it is widely understood there are many different types of swings, with different sources of power, and different alignments, grips, and overall mechanics that work together to produce the swings. Most golfers are aware of this and they seek out coaches that teach a particular style that resonates with them. Pretty much every golf instructor understands that there is a certain 'look' to a standard neutral, strong, or weak grip AND that this will vary from person to person so what may look like a classically presented 'strong' grip is actually 'neutral' for a solid chunk of the population. Those that don't know this and try to play with a neutral look will just spray everything right with a slice as the clubface will consistently come into the ball open instead of square based on their anatomy and where their arms and by extenstion club want to return to.
By contrast, I'd say most, but at the very least a large portion of the pool instructor community still only understand the fundamentals based on visuals. Angles. This does not address the underlying functional purpose of those fundamentals in developing the correct types of relationships between body segments. Because they don't understand the underlying WHY of the fundamentals, they are not able to recognize when that same function is achieved in nonconventional methods. They just dismiss those as 'stroke flaws' because the look doesn't fit their neat (and quite limited) model of the stroke.
These guys can still help a lot of players, particularly those whose natural hangs and body alignments fall in the average range where the prescribed angles for alignment achieve the purpose of locking in a plane of movement. But those that naturally find themselves at the extremes of the normal range for the way their bodies naturally align and the way they are accustomed to using their arms are left with good looking fundamentals that just don't feel right often and experience sometimes 'on' sometimes 'way off' days as a result of their setup not matching their natural swing plane relative to their body (this is another thing that is common knowledge in golf regarding what plane the club swings on relative to the body and no coach would switch a student from one to another without good reason to believe their more natural plane is in fact a higher or lower plane than the one they've been taught to be on).
I think this is what Matt was getting at regarding the guys that come to his clinics who have very good grips and fundamentals (from a visual perspective), but just need very minor tweaks in order to get the function that look will promote in most people most of the time. A tiny tweak in finding how a position should feel will tap that player into what they are obv doing when they are 'on' and make them aware of what is missing when 'off'. Visually, the two setups may be so close they could be virtually indistinguishable (tho admittedly for the guys naturally closer to the extremes of the normal range for people can end up in very different angle stances compared to one another--def not a one size fits all matter).
By approaching each student as an individual with their own set of 'specs' if you will, setting up the right conditions within the body and the right feels for the player to recognize, a good instructor can get a player to have true fundamentals in their stroke suited to them, their body, and the way they prefer to move and produce force (check Matt's comment on biceps-triceps isn't for everyone).
Frankly, most pool instructors just aren't there yet and really it isn't a surprise because this stuff is just not in the pool literature I've seen and certainly not anything being parroted by well-meaning SL7s teaching their lower ranked players.
Most instruction is cookie-cutter, one-size-fits-all, and as a result is just bad for a lot of people. Many, even high quality instructors limit themselves to one or two techniques they are very familiar with where they know all the parts fit together very well to produce a very functional stroke. But it's one stroke, with one look. And it will either 'fit' with a student's body and natural mechanics, or it won't.
When we get to the point where concepts that are accepted as common knowledge in various other sports, not just golf which is the gold standard imo, then we can entertain thoughts of pool instruction being out of it's adolescence. As things are now, there is one concept in particular that can be found in golf books from the 1800s....not a typo... which is perfectly in line with modern understanding of vertebrate movement, which most pool instructors aren't even aware exists. Seriously. Till we close that gap with other sports, considering pool instruction in its adolescence may be an over-estimation of how developed it actually is.
