So are you actually seriously arguing that being in a loving/nourishing/positive/encouraging foster home, has no advantages over being in a bad foster home?
Is that something you really believe?
If you are really seriously putting forth such an argument like this...
then I would have to STRONGLY disagree with you, and I would venture to say that if you had been put in a very bad foster home, and then very good foster home, as a child, you wouldn't be making this kind of statement.
You would know what it is like, as a child, to be in a bad home, versus good home.
In fact, the same also applies to adults. Do you currently (assuming you are an adult) live in a good/positive home, perhaps with a spouse, significant other, or family?
If so, would you give that up to go live in an abusive or highly negative, or cold non-encouraging home?
Of course you wouldn't.
So, if you would NOT want their for your own life, then why would you make a statement that it would not matter to her life/development?
Also, as the article linked by the OP clearly points out, when she was in good homes, her progress improved significantly.
But when she was in bad homes, or indifferent homes, or even abusive homes (such as when she was later beaten in a group home for vomiting) she regressed very badly, and collapsed back inwards, upon herself.
In short, your statement has me astonished and baffled... as again, it seems to almost imply:
"It doesn't matter if they placed her in a group home, that beat her because she vomited, versus a loving family in which she showed significant signs of growth... she's broken, so what does it matter."
Well... for many of us it DOES MATTER.
Just like for you, I would be willing to bet that it matters strongly what kind of home you live in, and you would likely NOT want to trade living in a loving home, for an abusive, or cold, or indifferent, or non-encouraging home.
She's still human, and with much of her progress she proved you are wrong about her, and she proved that she was NOT so broken that she could not be fixed.