If children in English-speaking countries are ever going to be consistently educated about the phonics structure of English, we will have to first decide that doing so is good public policy. Given that, I see the problem of introducing an effective and consistent phonics curriculum into all schools in any English-speaking country as three-part.
The Need for a Consistent Curriculum
First, effective phonics curricula have to be designed. To a large extent, this has been accomplished. The problem is that there is more than one program, and they aren't necessarily consistent with one another. This problem, however, would sort itself out eventually if the country ever decided that teaching phonics was essential.
The Need for a Standardized Phonics Code
Second, because even good phonics curricula are inconsistent with one another, public schools should, at a minimum, agree to teach the same phonics code. The reason is that most English-speaking countries now have very mobile populations, with children moving from school to school, often even during the school year. A child should be assured of being able to move into a new classroom mid-year and find that he is at least being taught the same phonics code as at his former school, if not the same curriculum.
Today, this is rarely the case. In two adjacent classrooms a child in one room could be learning that the gh in right or fight is silent, while in the second room a child could be learning that the igh in right and fight is the /ie/ sound, even though both teachers are supposedly teaching English phonics. Incidentally, if those two students marry someday each other and together set out to teach their children to read, wouldn't one expect some confusion over how to proceed?
The Need to Consider, and Remedy, Physical Limitations
Finally, an essential third requirement is that when a child struggles to learn to read in spite of being taught with a good phonics curriculum, we must learn to look for physical reasons for those struggles. In particular, we must ensure that they aren't dealing with undiagnosed problems involving the vision skills required when reading.
Instead, in most schools today the approach has been to jettison the phonics program in favor of an alternative method, usually a whole-word memorization approach, when the phonic curriculum doesn't appear to be working for some children.
Unfortunately, the search for the physical reasons a child might be struggling to learn to read is not now standard procedure, nor is that likely to be the case any time soon due to the perceived expense of doing so. But failing to take this third step virtually assures, in my opinion, that the longstanding "reading war" between phonics advocates and whole language advocates will continue well into the future.