This used to be the deal in California. During the 1950s and 60s lots of kids from Yugoslavia and Italy, some from Japan, some from Mexico, were taught English by English-speaking teachers. There was an immersion class usually lasting a month or so, or however long it took for the individual kids to learn enough English to participate in regular classes.
Guess what? They all did it successfully. They wanted to learn English. They were happy to be in this country and they wanted to be American. I still know some of them to this day, and they may still have a trace of an accent, but are fluent in English and in their native language. This didn't cost the taxpayers a cent extra. No one argued about it because it was the right way to do it.
Now the sheer numbers of immigrants here in California, legal and especially illegal, are costing the taxpayers a fortune.