I'm sure it's possible to raise children without slings and wraps. I just don't know how it's done.
By the way, Sophia is bundled up in a Moby wrap...snug as a bug in a rug. Out of the wrap style carriers that I own, this is my favorite for itty bitty babies. It's got just the right amount of stretch. If you can only buy one carrier, though, a stretchy wrap should not be it. The stretch gets uncomfortable once the baby gets to be around 20 pounds. And, no, I'm not getting paid to tell you my opinion...unfortunately.