I agree with the original post, and I would add, that the books have changed but not gotten any better, IMO.
The stuff my kids have to read has become more contemporary, but it is more focused on imparting a message. The books all seem to involve poor children raised by dying caregivers (often the biological parents are already dead or missing). These children usually live in some less favored culture: a lower income country, a repressed minority, or a similar downtrodden life style. The kids themselves are bullied and treated unfairly.
IMO opinion depressing books don't make fun or interesting books to read. Your opinion may well be different, and that is the exact issue. If your goal is to encourage kids to read then you need to have them read things they consider fun, not what you or I enjoy.
At the grade school level this approach is encouraged. There are several systems that rate books based on their reading level and length. Students are encouraged to read at their level, but they are allowed to pick whatever they wish.
By the time they get to High school, this approach is dumped. Selections are chosen for the student and it seems the selection criteria is that the book must either 1) be old enough to be a "classic"; thus requiring the reader to labor at translating the work into their modern day mind set, or 2) posses some deeper message on the lives of the poor, downtrodden, or otherwise dispossesed by mainstream society. It's no wonder students don't choose to read once they graduate.