Thought this would make decent fuel for discussion.
I think it probably depends a LOT on where you live. ds went to high school in a) a low population, low income semi rural state (lots of small towns) and then in a remote area of a large state and to be quite honest, most of the impetus for achievement in both places seemed to come from the kids themselves. The standout kid with lots of AP classes and also an excellent violinist (not my student) who took freshman calculus at a semi selective college as a high school senior was driven purely by herself...but her dad was a prof and her mom had a business, so she saw what being a high energy driven person could do for her. The kid with the $1,400 violin was a "sleeper"...the kind of kid who seems to have a lot of talent in a quiet sort of way, but not much motivation: she went to a pricey selective college and then did graduate work...despite her inability to find even five minutes a week for violin practice. One of the most talented low achieving students I ever had went to college on a soccer scholarship...sports won out over violin lessons eventually but he played in orchestra through high school. I can't think of any of my long term students that quit orchestra...but to my knowledge most of the ones that are still playing came from musical families. The only kids whose parents "pulled the plug" did so for economic reasons...they could not pay for lessons, and when I told the mom to not worry about it, she told me that she didn't want her kids "taking things for granted"...wanted them to know the "value of hard work". And she is still a very good friend.
Ladybug, in our area lots of schools have unweighted grade points. That is to say, general track is 4.0 for an A, college prep is 4.0 for an A, and honors/AP is 4.0 for an A. Creates some interesting incentives.