The best kidlit is the stuff that can be (re)read as a grown-up and still resonate, the stuff that doesn't write down to its audience.
Though I think the tendency of book awards to praise tragedy-tinged kidlit (lookin' at you, Tuck Everlasting and Where the Red Fern Grows, etc.) shows a bit of a grown-up bias, marveling at the depiction of pain and loss and the Important Lessons learned about mortality while forgetting that, as a kid, you knew darned well that bad crud happened and didn't really need to the dog to die in all the books to remind you...
As for whether a kid would enjoy a story set in the childhood of an "obsolete kid"... as the saying goes, history may not repeat but it often rhymes. The settings and specifics may change, and societal expectations of childhood and family may shift, but kids still face a lot of the same emotional struggles and development steps as they always have. As a quick bad example, the pioneer kid uprooted from their old life and drug to a new and strange frontier town is the kid whose parents' dotcom jobs busted so they have to leave the city for some spot-on-the-map is the space colonists' kid arriving on a new planet: coping with circumstances and decisions far beyond their control, trying to make new friends and figure out how things work and how they can fit in (maybe hoping for an opportunity to reinvent themselves, and discovering that it's not that easy), struggling to cope with the loss of old communities and routines, watching parents try to make a go of a new life (and probably being too busy to help the kid who may also be struggling)...
As for me, I enjoy many of MG and YA books (and even a few children's books). Bruce Coville, Jonathan Stroud, K. A./Katherine Applegate, Jessica Townsend...