The trouble with this is that it's accurate that for most people language acquisition does indeed require regular use and necessity and thus the majority of arguments against this are moralistic and not practical in how you actually get people to be bilingual collectively.
Everything about official bilingualism in Canada is built on myth. People can’t “just learn” a language they don’t need. Canada isn’t “built on” two equally-sized language groups. Bilingualism isn’t “necessary” to function at an elite level. It’s all just Laurentian folklore.