And that's fine. Societies can only function if the yield from the people it invested in is higher than the investment. This is why socialized healthcare is tricky. If you invest too much, you might be wasting resources and endangering all of your society. If you invest too little, you might be leaving people who would otherwise be productive once the investment is made.
> Are some simply too broken to fix?
There is no one too broken to fix but how compatible people are with their environments. A duck will leave its baby if it thinks it can't cross the river. Its brothers did cross, and thus it has to go forward, carry on and leave the weak behind. On the other hand, if the duck was living in your backyard and eating from your food; it would not have to do such a difficult choice. Its baby will not need to cross any river and thus it'll keep taking care of it.
> I feel awful thinking this, but I wonder if there is some truth to it.
It's life. Netflix has great series (Planet Earth) that you can watch. We are not really different from animals, we just happen to live in a different environment.