Or to put this another way, your wife adopts an expectation of underachievement and, unsurprisingly, it pans out so?
Quite possibly - but just perhaps my 'Outstanding' rated teacher wife is not supported by some parents (if the kids have parents) who as well as conforming to stereotypes regarding naming also do nothing to support their children through the most important years of their lives. I can also tell you that the greatest pleasure my wife gets is from helping a pupil succeed despite their upbringing and parenting. Unfortunately this is not the norm, some kids can make it, but unfortunately most don't. Stereotypes exist for a reason - no matter how fair it is.