Years ago after a mum had given birth,they weren't given the chance to bond with their babies as they were whipped up and taken straight to the nursery. This was in the 60's/70's. When I did a stint on maternity I took this as the norm as us staff had the jobs of feeding the baby if it was bottle-fed,otherwise they were then handed to mum to feed,then immediately wheeled back into the nursery.
My step-granddaughter was born breeched and 3 months early so was kept in hospital and could only be " viewed " through a window. The baby was just over 2lb in weight and was kept in hospital for 3 months until she weighed 5lb. My step-daughter was petrified of holding her when she eventually brought her home and flatly refused to have anything to do with her so I had her mostly while she was growing up so there was no mother/baby bonding at all.
However,we all got through it and mother and daughter are fine. She is a strapping woman with two of her own children and step-daughter can laugh about it with her but no damage was done.
How other babies got on I don't know but I shouldn't imagine that they came to too much harm as nobody knew any different in those days. My own daughters were treated the same.Whipped away and put in the nursery. They weren't any the worse for it as too much is made of some things at times and if the past situation is drilled into you that's when autosuggestion can do damage that it dwells on the sibling thus causing unnecessary problems.
I'm sure it's not what you mean, but it SOUNDS very much like burying your head in the sand. ie it worked for me and my family, there's no reason for it not to work for others. It seems fine now, but I'll bet, however grateful she may have been to you, it was a miserable time for your step daughter when she had to watch you bringing up her child
I'm certain that it did work for some but that's not a reason for not trying to make it better for those it didn't work for. It's easy to say that they "weren't any the worse for" the experience when we've no idea how much better they COULD be.
If we don't try to move forward, nothing will ever advance. If we say things are fine for the majority so no need to do more, the MINority, ie the mentally ill? will suffer.