I think a lot depends on a child's personality and temperament, and its a parents job to meet a child where he or she is. Clearly not all techniques work for all kids even in the same family born of the same parents. I come from a tradition of fairly large families where 4 - 7+ kids is the norm. Even in the most loving of families, when you have enough kids, there are definitely people with "issues" - whether or not those "issues" become things that derail their lives is, I think, often a result of how responsive and flexible the parents are to their children's needs. One size does NOT fit all, even in the same family.
It has been proven time and time again that "authoritarian" and "permissive" parenting are not good choices and that the approach that yields the best results is "authoritative." There's a wide range of styles and techniques that fall under that umbrella, from AP to whatever the opposite of AP is called.
Hopefully, parents and children match in temperament more often than not. I have friends who are very regimented people who fall apart when they can't adhere to their schedules. Luckily for most of them, their kids are the kind of kids who thrive on and require predictability day in and day out. Those kids would not have lasted long with me and I would have had a real hard time making sure that life came to a stop at X hour because my child had to be in a certain place, at a certain time, doing the same thing in the same order every day or he or she wouldn't sleep and there'd be hell to pay for all. Likewise, my friends would have gone crazy with kids who slept whenever they were tired and ate whenever they were hungry.
Likewise, I have a friend with lovely children who has never breastfed (mom thinks it's disgusting and an imposition) and would never, ever have a baby sleep in her bed. I would no sooner have a baby sleep in a crib in a room down the hall than I would leave an infant in the basement or garage. For me, that's too isolated and too far away, but she said her kids enjoyed sleeping in their own space from day one and who am I to disagree?
At the end of the day, the only kids I'm raising are my own, I do what works for us, change things up when they're not working, and hope that others do what works for them and are also open to the fact that our kids throw new stuff at us every day and our job is to adapt.