I think many, if not most, people learn English to better their job prospects. I read somewhere about the number of people who study/speak English as a second or foreign language, and although I can't recall the number it was staggeringly high.

My point was that speaking fluently is the goal, not necessarily speaking like a native speaker. A foreign speaker of any language usually has an accent, and has a somewhat simpler vocabulary, less synonyms: for example a non-native speaker will go for a walk, while a native speaker might also take a stroll, etc.

For the great majority of people I have taught or met (hundreds over the past 10 years) the finer points of English are surplus to their needs. As they are to many native speakers, as well.

A good non-native teacher is better than a bad native speaker teacher, and for many students possibly as good as a good one.

Of course a bad non-native teacher is worse than a bad native speaker teacher, in that the native speaker offers something just because he or she is usually fluent enough in English to provide some language input, even though it may be boring.