I would not flatter the JWs, or Brooklyn, or the FDS, or Russel, or Rutherford, or any of the great lights of the JW experience with the word 'myth'. Any good leader takes the best of what his people offers and guides or facilitates them in that direction; he has the 'mandate' of the people. Any good textual representative of a people (eg Homer) takes the best of what the people believe in their daily lives, their traditions, their etiologies, their sentiments about wind and weather, and distills them, along with peers (eg Hesiod), into a barely coherent but extremely compelling narrative that lives on far longer than its language of origin. It says something often true, and often crude, about our reality.
JWs expect someone to get fired up and give a crap because Jesus came invisibly in 1914. Nope, sorry. JWs do not qualify for the word 'myth'. Their storyline is derivative, arbitrary, top-down not bottom-up; they do not seek to represent the daily lives, traditions and etiologies of their rank and file. Instead they seek to impose those things to a conformity. JW doctrine attempts to cover all bases so hermetically that they invent God's intentions and hidden meanings in terms of blood, birthdays, etc. JWs own God, control his voice, control his meaning, and make him do their bidding. "Jehovah" is their brand name, after all. They could be "Jehovah's Handlers" for all that. Mythology is more open to daily experience, and not a dogmatic policy text.