JB, respectfully, this literally describes any aiming system, even HAMB. The more you use it, the more you can rely on it, be it aiming system A, B, C, or no conscious aiming system at all.
I disagree for the context of the discussion. Of course you can rely on that which you have practiced to proficiency but what you cannot "rely" on is the same level of consistency from one to the other type of method.
I am constantly testing this out by shooting by "feel" versus systematic aiming. Ideally I would love to be the type of person who doesn't need to spend any time measuring the shot and could just see it. It FEELS great to simply get down and shoot but speaking only for myself, my ability to be consistently successful goes WAY DOWN very quickly when I try to shoot without using any aiming other than what feels/looks right with nothing other than maybe contact point and "shot pictures". Although I can say that "shot pictures" are, for me, kind of a really unused and in my opinion marginally useful way of "aiming".
HAMB can only be considered as reducing subjectivity in terms of muscle memory conditioning shot by shot. But where it breaks down is when the shooter is faced with conditions outside of that they have brute-force practiced to that point.
Consider this example;
you have two players who have both read Bob Byrnes Standard Book of Pool and both have been playing for six months. They both have decent fundamentals and have developed to be functionally equal. Other than that they have had no instruction, no knowledge of any "objective" aiming systems.
Player One is taught an objective aiming system for one month and develops adequate demonstrable proficiency, one with very clear aim lines/fractional perceptions. Player Two is not taught anything else and continues to practice shot by shot repetitively. At the nine month mark the two players are tested for shot making acuity using various tests with a wide variety of shots. Many of the shots are shots that neither player has actively practiced until that point.
Which of these two players is likely to score higher?
I am going to say that it will be Player One. The reason is that Player One has a way to figure out the correct aim on shots that he has not practiced. Player Two is likely to score significantly lower due to the unfamiliarity with the shots.
Ok, now what if we go another month and player two has now practiced the shots that he did poorly on. They retake the test and what is the likely outcome?
I submit that Player One is still going to score higher but that the score will be closer.
Why? Well I look at it like studying for a test by memorizing the questions and answers versus studying for a test and learning a logic system that can be applied to any question. To me a good aiming system is a logical framework that can be applied to almost any shot. So I would expect that Player One, having more experience in the application of that framework is likely to be less inclined to be influenced by concepts such as difficulty and uncertainty in the aiming. There is not likely to be a running "score" playing in that shooter's head about past success/failure percentages for any given shot they face.
Player two SHOULD score higher than they did previously but only because they practiced the shots they failed the first time. But I doubt that they can outscore Player One on that test at that point in their development.
I would even go a step further towards creating some kind of "proof" for this by making Player One take a different test where the shots are similar but slightly more "difficult" according to how we look at shot difficulty. It is my opinion that Player One would still outscore player two in this situation and be able to match their previous score or exceed it.
Conversely I think that if Player Two were given the "harder" version of the test then they would score lower than their second time with test one.