It usually does. But I think such parents have distorted perception. When parents were blue-collar kids, they studied at lower-grade schools, and with some persistence could get high grades. This allowed them to get to university and move up by social ladder. (Even though, there's been a trend that more % of people get higher education.)
And then they set much higher standard for school, sending children to where it's really hard to get all A-s, even though the kid performs pretty well, way above the nation average.
And then they set much higher standard for school, sending children to where it's really hard to get all A-s, even though the kid performs pretty well, way above the nation average.