In my experience with what I call "Older Order" and "Oldest Order" the retention rate is much higher than 80%, and criminal problems (i.e., the child abuse you mentioned) a small fraction of non-Amish averages.
Indeed, I'd say that for your figure of 80% to be remotely accurate they must be counting Amish who move from one Older Order settlement to another maybe not so "Old".
Of course Amish are human beings and like all humans are fallen and fall short of God's glory.
But they are sincere in their beliefs and in my experience do a better job with their own youth than us non-Amish on average do with ours.
I’ve not had, nor have my family or friends in PA who have Amish neighbors have ever had any personal dealings with the Amish that were negative and while there may be some bad apples among them, those that fall short, yes being “human” like all of us are, I don’t think that is representative of all the Amish. But the insular nature of their society does sometimes lead to sweeping things like sexual child abuse under the rug as they would rather deal with it themselves rather than brining in the police, the legal authorities.
OTOH, truthfully the CPS and other governmental agencies and courts have not always done an exemplary job in this area either.
As to the puppy mills, and not at all to defend their practices (and I do not advocate buying puppies raised by them), the Amish see dogs as a commodity and right or wrong, they see breeding dogs much like they do raising chickens or pigs or cows.
But then there is the amazing side of the Amish as was shown after the Nickle Mines Amish school shooting.
The love and forgiveness that the Amish community, including those parents whose children were killed, showed to the family of the killer, to his wife and his mother and father, is something I think all people should strive for in a time of great tragedy.
Amish Community Forgives Family After Schoolhouse Shooting - Crime Watch Daily
Amish School Shooter's Widow Finds Peace in God
Forgiven: The Amish School Shooting, a Mother’s Love, and a Story of Remarkable Grace
There was also the case of a young man in Indiana, Chandler Gerber who was texting while driving and slammed into the back of an Amish buggy, killing three people, the mother and two of the children.
Shortly after the accident, he received a letter from the father, saying that he had forgiven him and wishing God’s grace on him and wishing him and his family well.