ah, hide the hard one at the end :)
Income equality isn't "hard" if you look at it logically versus emotionally. Raise taxes, ensure a proper social safety net, widen the middle class.
Then again, this is America. We try everything else first before the right way (apologies to Churchill).
Income equality is hard when you start tracing where the income actually comes from. Furthermore, the parent said "broken homes," not merely income inequality. A poor household can still be a stable and positive environment.
Both select for teachers of above average intelligence but the way those teachers are taught is very different.
The kids in poor broken homes thing is something Finland is having more of, due to recent not-so-sensible immigration. There's very little one can do about it without draconian measures -- handing out money doesn't help.
I do agree with you though, there's things that can be learned from these countries with respect to things like demanding more of teachers (master's degrees) and rewarding teachers more (not just decent, but great salaries which involves seeing teachers like you see doctors). That makes a lot of sense. Our requirements and rewards for doctors are a lot higher, despite the fact every single child is raised and educated for half of every working day's waking hours for more than a decade, teachers have absolutely insane levels of influence on something many of us value to extreme levels (children), in Finland resources are allocated accordingly, in the US not always. So I agree there, but I still think differences between e.g. Finland and the US have much more to do with your last point: making sure kids aren't in poor broken homes, which isn't a direct educational policy theme and requires mostly deep socioeconomic policy changes outside of education.
And I suppose that trying to impose uniform policies on a not-culturally-uniform group doesn't help either, especially when you add in hypersensitivity and the polarization that comes from everyone not knowing everyone else.