I think that there's inherent value in common education, which is that value the French revolution promoted as 'Fraternité'. If we're so worried about immigrants not becoming Canadian enough, the answer is to blend them into classrooms where we have control over what they're taught. Charter schools will lead to separation and disunity IMO.
'Leading in math and science' is indeed a measure of how we're doing, but it's not the only one. Only a tiny minority of students will use these skills as a daily part of their job. The most important things that they learn are difficult if not impossible to measure: teamwork, industriousness, civic mindedness.
But, unlike some, I feel that we need to listen to people who have complaints about the education system, just as we need to listen to complaints about the health system and justice system. For those of you who have students in public schools, I ask if the board/school provides an easy way to give feedback on their programmes. If so, have you tried to engage with them and how have the results been ?