Pregnant and breastfeeding his friend

Peace and blessings,
There are two main reasons for the prohibition against carrying a child from a fellow believer: to determine who the father is, and so that the child will not become a sandal.
The main reason for the prohibition against carrying a friend's breast-feeding is that the baby will not be harmed by the loss of milk.
The question is: Since we now know that a fetus is not made a sandal in a beila, and since we can distinguish who the father is with a simple DNA test, and since today milk substitutes are available everywhere, is there no reason to say that this regulation, which was intended to protect the fetus/infant, no longer protects him but, on the contrary, harms him? After all, it prevents him from being a potential father, and not only that, it also prevents his mother from being loved and happy (which will usually have a very positive effect on the baby or fetus and its health). What's more, after all, we live in a world where a standard woman is a completely independent person and is not subject to a husband or afraid to sue or anything like that.