I appreciate that. But at this point, a lot of the evidence is still anecdotal. I teach English to francophones as well, and I'm shocked at how many francophones cannot progress professionally because they don't have enough English. So maybe if there was more English in their school, it isn't by definition a problem....
I meet many professionals who are stuck professionally. That's why they come to me and they pay many thousands of dollars to come to me--and arguably too late, because you should be doing this when you're in school when you're a teenager.