In my opinion, this should not necessarily be a grim conclusion, but yet one more reason to consider poverty eradication. It's the kind of perspective that can be both scary and motivational. As the article concludes, building a healthy brain, it seems, is a community effort.
We can measure how poverty impacts the brain development, but not really how that impacts behavior, cognition or things like decision-making, problem-solving or learning abilities.
From what I gather, the science shows that deprivation can result in a smaller hippocampus and brain surface area, which could relate to some of these abilities. But it also shows that in the middle and upper levels of the income curve, the differences are negligible. This is to say that income, below a certain threshold, is an issue.
Science can tell us how humans react to certain stimuli, but that "law" does not guarantee every human will have that same reaction in that same scenario. The laws of behavior are today similar to what fractals were (in maths) before Mandelbrot: unpredictable.
And this type of science will tend to be less concrete and more abstract for a really long time, due to the very nature of the human brain and human behavior.
This is not to say the science is wrong, but most of the predictions concerning the cause and effect of human behavior or personality should yet only be seen as a generic trend, a sort of a plateau of plausible scenarios. Science still has a lot of "fog" to clear in this area.
Meanwhile, we all know that we should eradicate poverty, for all possible reasons.
But there is also very strong evidence that the human brain's plastic abilities tend to surpass these types of pre-determined conditions. Things like ambition, curiosity or perseverance shape the brain and impact behavior.
Poverty should concern us regardless of its actual impact on the human brain.