The "old fashion" way is actually to keep your babies very close to you and to sleep with them
That is how humans started out and it wasn't until more recently that people started not attending to their crying babies and having them sleep in seperate rooms.
We bed share and created very indpendent children. Studies show that bed sharing/co sleeping and attending to their cries create indpendent children (and that goes beyond the first year). Kids who are very dependent is more likely due to other factors than sleeping with their parents, unless they are forced to, which isn't a normal bed sharing relationship.
'Old-fashioned' in my terms is what my mum and aunts would have done. With centuries of parenting behind us I guess the term old fashioned can mean virtually anything lol!
Studies show all different results - depending on what you are looking for and that comes from a health professional who is used to years of studying child and adult development. I fully respect your opinion and what works for you is great but would like to reiterate that I do not ignore or withhold attention from my babies when they cry - simply that I do not pick them up and cuddle them every time they cry. I 'think' at the end of the day, all babies are different but what can impact or influence how a child develops confidence wise is more to do with their parents attitude in general. A mother like yourself who is happy and relaxed with co-sleeping is going to have a happier baby than a stressed mum who gets stressed with feeling they have to lift/cuddle/sleep with their baby. Babies pick up n these feelings and I think there is a lot to be said for happy mum, happy baby - stressed mum, stressed baby.
Not all mums enjoy constantly carrying their babies around, especially if they are tired, have other young children or are in physical pain doing so - therefore they should find another way to deal with crying which creates a win-win for both mum and baby.