Japan has "offered" foreign language education starting in junior high school limited to english for decades. it has started to consider starting even earlier (primary school). private english language schools here are a booming business. and recent a prime (obuchi i think) even had a commission propose that english becomes official language in japan. and they don't have much goats to herd here i can tell you.
besides, results for all the tests related to english skill (toefl, toeic) have been dramatically low, and getting lower (i think they are the lowest of the area, needs confirmation).
you mention "vernacular" opposed to "latin" in your post. but i wonder if there is not something more. first it seems to me in the age of latin there were not the communication (cultural alienation ?) tools that we have now thus you had to be physically present _and_ represent some kind of power to force your surrounding to speak your language.
now commodities (not limited at all to cultural commodities), not people, are candidates for this physical presence. ultimately, the choice (as seen from the commodity maker) is not whether he'll have a worker fluent enough to understand directions in english while working in the plant, but whether you have a consumer population able to the commodity as is, ie without the mediation of translation.
monolingualism is not so much about the worker, it is about the consumers. that's why gatt negotiations in the 90 had the "exception culturelle" at their center. the burden of translation is not on the maker anymore but on the consumer (ie on the importer's education system, not on the exporter's).
there was a similar comment on a translator's list about the fact that french speaking researchers had to publish in english even when they want to communicate together... obviously researchers are not linguists/translators, so the burden of writing their papers in a foreign language is that much energy taken away from research, which ensures in one way that english "native" research whatever it's quality is always at the top.
jc helary