Nobody pays for a course to learn what a candlestick is. They pay for one promise: "after this, you will be profitable." So there is exactly one yardstick: does the method's output equal profit, or not. Everything else — hours of video, number of students, production quality, books and apps — is irrelevant to that question.
And if a method is genuinely profitable, it can be written down completely: entry condition, no-entry condition, stop, target, size, risk. Once fully written, it is no longer a "skill"; it is a tool. A tool gives the same output to anyone who executes its instructions. A method that only works in its author's hands is not a method; it is a person. And you cannot sell a person.
100% rule-based means 100% reproducible, not 100% winning. A mechanical system has drawdowns and red months too. The difference is that in a red month the author and the executor lose together, and everyone can see it.