The answer is simple and as dramatic as it sounds, it's true. It's the end of the world for a baby as she no longer gets the full attention she's used to, she doesn't take her twice a day long walks, she can't stay into her mother's arms for as long as she wants (and no, this is not spoiling, all humans need to feel loved once in a while).
If the mom is still breastfeeding it's even worse as the special bonding between them is gone. Breastfeeding is not only about feeding the milk to your baby but especially about a strong, unique way of bonding with her. Babies don't breastfeed only for food but especially for comfort, the psychological factor is way stronger than their physiological needs, that's why they don't eat as much as the bottle feed babies and they ask for milk endless times a day.
I am no longer breastfeeding my baby girl but I bottle feed her in the same position I used to breastfeed her, right next to my breasts, while singing her favorite songs and holding and kissing one of her hands as she likes to touch my face with her tiny, sweet fingers and then be softly kissed. We've always done this and if for some reason we deviate from this routine (like now, when I'm very, very sick and in big pain and try to avoid spreading my germs to her by covering my mouth and nose while she gives me such a scared look), she refuses to eat properly, she only takes about half a bottle. And since I don't have the energy to take her out or play with her during meal times (I know, it's wrong but it gets her to eat), or sing as I have no voice left, she doesn't eat solid food as well, just a bite or two.
Her bed time routine is also slightly affected as I also used to sing to her at bath time and then kiss her all over her tummy, arms and face while putting some lotion on her, jut to get her sit still. So good bye peaceful bath time! And good bye falling asleep right away as it takes between 45 min and 1 hour for her to fall asleep now while mommy holds her breath hopping her baby won't start angrily crying.
If this awful situation lasts for too long it definitely changes the baby's good habits and the mom has to start everything all over again, this time with less hope and results as the baby is older and harder to train, she already developed her personality and she strongly sticks to it.
Babies are so ambitious! How else they could learn to adjust to our tough, full of strange rules world!
If it could only last for a life time.