BTTT
It surely depends on the parents. It's likely that the smarter kids, with the greater expectations, are those children of parents who work hard and smart, own property, a portfolio, and care about their children's grades, and awards, and capabilities, etc. I still think that those from the affluent middle class background, if they don't descend into brattyness, feel they have been given the most and work most confidently to give something back, their entire lives. I think others find it more difficult. And I think some, those penniless who work at a dead end, might some of them find it even more difficult to even vote Rep, unless they also have the support of a large family where each plays the small role alloted.
But - yeah - you can see how anyone can generalize.