There's a difference between what you
want to communicate, and what the words you type end up actually implying. I understand that you said "I'm not saying that [...] homework should be shitty to prepare kids for reality"—but saying that there are shitty things that should be taught, because that
is reality, is the same idea behind a different facade.
We live in a socially-constructed reality. There are laws of physics and biology that say how the world around us acts, but really, we get to decide how we act, and make the rules for human behavior. If you entitle a group to an idea, make them think it is perfectly deserved—even if their own elders can't give them that thing—then, when they grow up, they will give the generation coming after them the opportunity they never had.
Entitle children to the idea of human rights and, having grown, they will not own slaves, and free those passed down to them. Entitle children to game-designed work, and, having grown, they will believe that game design has a place in I/O psychology, and that any organizational consultant worth hiring will need to optimize for fun.
Now, you might rebut with "but what about those laws of physics and biology you mentioned? Surely they necessitate some form of un-fun?" The interesting thing about that is, evolution has made sure that all the things we have to do to survive and reproduce are fun already.
* Running (and hunting, catching, killing), and exploring (and gathering, washing, preparing, and cooking) are both fun.
* Having sex is fun (think about how arduous procreation would be if evolution didn't make us think otherwise!)
* Being creative (telling stories, doodling, humming a melody to oneself) is fun.
* Competing and collaborating are both fun.
* Inventing and using tools is fun, as any programmer would tell you.
* Understanding why things work the way they do is fun (and funny! Laughing is the basic response to a sudden realization that makes you dump cache and re-parse a narrative.)
Other examples abound—the only things that aren't fun are the things we force ourselves to do to live in this strange, post-agricultural lifestyle—commuting, being "objectively evaluated", producing things that disappear into an aether and for which one never receives feedback from the people on the receiving end... we're not going to change this process from the end-side. School beats people down and makes them accept this kind of life, and thus they won't bother to change it once they get there, even if it could be better. We need to entitle these new people, to make them angry that they aren't getting something because it doesn't exist yet, so that when they get the power to do something about it, they will.