Essentially, what Jack discovered, formatted, developed, or whatever you want to call it, is a framework and a set of logical principles that all liquid markets naturally conform to.
I was thinking about how to describe TA to people who don't have any exposure to the field at all, and the best I could come up with was that it's similar to when Neo ascends or something and starts seeing the flowing green code in the Matrix instead of the normal image of the virtual world they're in.
Anyway, to answer your question, I used JH's materials to help me teach myself the language of the market and trade according to the sentiment it's displaying on whatever fractal I want to partner with. I wouldn't say the methodology is his in the sense of ownership. That would be like saying the laws of physics are Newton's methods of how the world works, to give a crude example.
The DB/Wyckoff material is quite similar in it's fundamental premise, only the focus has more room for subjectivity and analyzes behavior while JH is completely technical with the use of price tick movement and amount of volume as it's variables. However, as far as I know humans have yet to create a highly liquid and freely traded market that doesn't conform to both of these " methods' " fundamental principles.