How does context affect bilingualism?

Hamers and Blanc (2000) make the process of defining bilingualism a little more challenging within that first chapter, as now we should also be considering not only cognitive processes, but also social interactions, and socio-psychological aspects as well. That is not only the ability to understand and perform within a second language (L2), but how the context of our situation makes us feel toward a language, and how much we are encouraged to valorise (attach positive value toward) the language systems around us. In a monolingual environment, that may be nil. In a bilingual or multilingual environment it would depend on the prestige attached to the respective languages.
That brings me to question my environment here in Japan. It is essentially a monolingual environment (Japanese), but English seems to be promoted as 'the' language to learn to get ahead. Yet, it seems like it is more said than done, as English levels remain low (according to standardized tests such as TOEIC, etc), at least compared with other Asian countries. Does English have any prestige, or enough to make people value it and internalize it? Are the forces (pretty much everything is Japanese first) at play in this essentially monolingual environment too strong? I know that every time my students (college kids) leave their classes, the pressure to speak Japanese can be seen, because I see them quickly change to their first language (L1). The only exception I see, is with our International High school kids. They seem to continue speaking English in the halls, almost in a kind of defiance or to show themselves capable... Could age and development, as two of the dimensions of bilingualism be strong players in how confident students are in going against societal norms?
I don't know really, but I think that as students get older (here), they start adapting to behavior of the group, and often the nail that sticks up, is hammered down... Kind of a negative view, but Japan tends to favor group behavior rather than showing individualism. And speaking English (well) here is still considered kind of special.
Ciao
Steven thoughtful