Would Mozart have been a musical genius if his father had been, say, a carpenter, not a musician?
He wouldn't have.
That seems obvious.
His home environment and the education he got must have played a decisive role in his life.
Decisive?
If my father had been a Leopold, would I have been a Wolfgang?
Of course not.
Leopold was a good teacher, as well as a good composer.
The role he played as his son't teacher, or his enthusiasm as a dedicated teacher, could not have been underestimated.
Who knows, had he been a less competent teacher, his son might have been a minor composer.
That said, education cannot be discussed simply in terms of cause and effect...