Yeah, this varies widely of course -- my parents didn't go to college and we were lower middle class but I was an obsessive reader. These are just trends noticed by various ethnographers. The particular study I based my comment off of is a fairly old piece (1982) by Shirley Heath, "What no bedtime story means: Narrative skills at home and school". This is by no means a quantitative, or recent, or widespread, study, but it gets at these issues very well and frames the problem much more eloquently than in my comment for sure! There are a few other studies like this, but this is just a memory from a course I took a couple years ago so I don't have sources immediately available. There's also the fact that you ended up going to private school, which probably has something to do with your observations; families who stress education enough to send their child to a private school probably also encourage behaviors like reading that play a role in how schools defines success.