Large numbers of function illiterates, that is.
A thorough grounding in phonics produces great readers, excellent spellers and good writers in far greater numbers, even at the low end of the bell curve or when parents are indifferent.
Illiterates yutes become feral yutes because they have no way to access civilization except through their peers.
Agreed. But teaching (or learning) phonics requires discipline and drill, which I believe are not high on the priority list of the groups you reference.
So if “see-say” were outlawed tomorrow, I don’t know that it would of itself make much difference.