You’ve left out a large chunk about how the various methods of teaching reading will create different neural pathways leading to activation of different parts of the brain. Read up a bit more on the science behind reading instruction…

And you’ve put far too much emphasis on home environment, forgetting that correlation does not equal cause. Everyone was illiterate at one point in history. How did a world full of illiterates manage to turn into a world where a very large proportion of its inhabitants are literate? Having a house full of books and reading to your child may encourage the practise of literacy skills, but it doesn’t cause them.

Dyslexia is a symptom, not a condition.