Why variation across cultures in SLA?

As a student of SLA theory, I think I can summarize a lot of theory and research by making this statement: we don't know what explains the differences in the ways people learn language, although we have a lot of ideas.  I have particularly been thinking about a few of those factors in light of my recent experiences.

This summer I had the opportunity again to visit beautiful Europe, which always helps me to reflect on my experiences both as a language learner.  This year I went straight from the Czech Republic, where proficient English speakers are relatively difficult to find, to Sweden, where speaking advanced English is the norm.

Surely I am not the first person who has wondered: why is it that in two European countries relatively close to each other there is such a noticeable difference in the proficiency of the general population in English?

(At this point I would like to insert the comment that I do not wish to imply by asking this question that people should learn English.  People are free to learn or not learn whatever languages they choose.  Nor am I trying to imply that I think Sweden is better than the Czech Republic somehow -- I have dear friends in both cultures.  In this post I am simply using the two cultures as an example of obvious variation in language learning success on an overall sociocultural level.)

Let's discuss some possibilities:
1. History.
During the communist time, Czechs usually only studied Russian or German at school.  If I recall correctly, the Velvet Revolution that led to the overthrow of communism and, ultimately, return of widespread English teaching to Czechs.  This explains why basically an entire generation of Czech people doesn't speak English, and why the most proficient users of English are likely to be elderly people (who learned it before the communist time) or younger people (who learned it after).

But this can't be the only explanation, because even just looking at the younger people there is a noticeable difference in the language learning success overall between Swedes and Czechs.  While they start learning the language at more or less the same grade in school, many young people in Sweden are highly proficient in English while their Czech counterparts are struggling with beginning-level vocabulary and grammar.

2. Methodology.
It is true that language teaching methods are different in different areas of the world, but I'm not sure that this is the explanation either.  When I first started participating in teacher education workshops in the Czech Republic a few years ago, we inappropriately expected that we would be preaching the merits of communicative language teaching and found ourselves quite humbled when we discovered that our Czech colleagues had heard it all before.  In the Czech schools I have worked in, the teachers have had access to the most updated curricula and texts for English language teaching and have learned current methods at their training colleges.

3. Language/cultural background.
You might think that, perhaps because Swedish is more closely related to English than Czech is, people who already have a background in Swedish would find it easier to learn English.  Research in SLA doesn't seem to support this line of thinking, however.  Studies have shown that, regardless of language background, learners tend to progress through the same stages when learning a new language.  In addition, Swedish and Czech are both Indo-European languages, and therefore neither of them is particularly far from English.

In a more subtle way, however, cultural factors may be at work.  In my experience, Swedes self-identify with Western Europeans and Americans closer than other cultural groups.  It stands to reason then that identifying so closely with native speakers of English in Britain and America may be a cultural reason that Swedish people seem to be more successful at learning English overall.  But can a slight cultural difference (the one between Eastern and Western Europe) be the explanation for such variation in language learning?

4. Exposure.
It does seem more likely that exposure to English is one factor in the differential English-learning success between Swedish and Czech learners.  While both groups have access to plenty of English-speaking television programs, movies, music, etc. in the original language, English seems to have a noticeable presence in Swedish popular culture that Czech does not.  English is more likely to appear on Swedish billboards, t-shirts, and so forth.  In the Czech Republic it is prestigious to have English words on your clothing, but the meaning of these words is apparently not important.  Or at least it seems that way because of the amount of "engrish" that can be observed on clothing in the Czech Republic.  In addition, because the population in general is less proficient in English in CZ, I could argue that people get less exposure to other people speaking English as part of everyday life.  For example, a Swedish friend of mine told me that her parents used to speak English to each other when they didn't want the children to understand what they were saying.  While she did not understand English at that time, she quite possibly picked up some phonotactic information or even rudimentary vocabulary and grammar of English because of that exposure.  Since highly proficient English speakers are still at a premium in the Czech Republic, the overall chance for a person to hear English spoken in or out of the classroom seems less.

5. Attitude/Motivation/Learner Beliefs.
Many Czechs that I have talked to have expressed to me the difficulty they experience in learning English.  It does not surprise me; I understand well that English has many irregularities and grammatical surprises.  In Sweden, however, an English learner is constantly surrounded with other people who use English proficiently, perhaps causing Swedish learners to be more confident in their abilities to learn English in comparison to their Czech counterparts.  Perhaps the fact that everyone else is doing it is the reason that Swedes can do it so well.

6. Strength of need for English as a lingua franca.
Both Czech and Swedish are relatively nonprestigious linguistically, so it stands to reason that the people would need a lingua franca.  German has been an accessible and historical lingua franca for Czechs, while Swedes don't have the same historical background with German speakers.  The area of the Czech Republic where I lived, for example, receives many German-speaking tourists but hardly any American or British tourists.  So perhaps English is not as necessary in the Czech Republic because German is more used.  Personally this point doesn't feel like the explanation to me, and I feel that I hardly know the history of language contact in Sweden well enough to claim that English is more necessary than German there.  Both countries, are, after all, extremely close to Germany.

I give this list as a set of possibilities, believing that some of them are more likely to be the correct explanation than others.  Feel free to add your comments and observations to fill in factors that I may have overlooked.