We don't give IQ tests and do home-studies for intended (birth) parents. We don't look at their debt to income ratio. We don't know if their financial status is stable.
And even with adoptive parents who fit the "good parent" criteria, their status can change. There are no guarantees, that's why none of these proposed "standards" of parenting would work anyway.
I have a cousin who was adopted at birth by my aunt and uncle.On paper they looked great. Married for ten years, both degreed, aunt was a tenured special ed teacher, owned their own home, grandma lived up the street. The birth mother was a college student and pastor's daughter.
Well, uncle was verbally and emotionally abusive to aunt and cousin. She left when he was 8-ish and they wound up in a shelter. To date he and his mother (he is 19) still share a one bedroom apt, he hasn't finished high school, is unemployed, can't drive, doesn't even have an ID, and has no clue what he wants to do with his life. I simply can't figure out how placing him with these "competent" adoptive parents made his life better. My point being, that what it looks like today, is not necessarily how it's going to be tomorrow.