Now you are probably thinking, why in the world would anyone do this? The truth of it is, there is a very good reason to do this. It is about extending the life of your doll and also to bring custom options that are not available on a stock doll.
Now let's break this down, starting with stock dolls. The manufacturer gets to choose what hair colors and styles the doll comes with. They get to choose the combination of eyes. Then they decide how many skin tones and which skin tones will come with those hair styles and eyes. Those are the choices you get. You can choose to purchase one of those and many are happy just as they come. But then there is the world of some of us that just want more. We don't want stock faces, we don't want stock outfits, we don't want to pick from a limited span of options. We want all the options. It opens the door to creativity and having the perfect doll to suit you. Because as we all know mass-manufactured means a product that is mass produced to GENERALLY appease the population as a whole. But anything custom or tailor made is designed to appease JUST YOU. It's as specific as they come and it comes with endless choices instead of limitations.
My example of this is going to be Gotz dolls, now of course there are many other dolls with rooted hair but this is my favorite example. Gotz dolls are very well made and sold on par with other brands of it's caliber. But there are extremely limited choices on each of their dolls, I mean very basic. And then on a limited basis they release small runs of very specific combinations that sell out and then aren't available any more. All the hair is rooted, which is lovely and nice quality and it seems a horrific type of punishment to take these dolls and cut off all their hair. It's very much the parent's nightmare when we were younger and playing with scissors and gave our doll the buzz cut or the half and half (half long half short). But these dolls are incredibly beautiful and incredibly unique when a high quality wig is added versus their stock hair and very desirable. In fact if you look onto ebay, even the stock dolls go for very high for their price point and the custom ones are even more expensive. I have several in my collection that I have completely customized and they are one of my favorite mini collections in my overall doll collection.
The second reason is to extend the doll's life. No matter what, there is going to be a point in time where your doll's hair gets nasty, unless you take her from the box and straight to your locked doll cabinet. This is especially true with played with dolls. With my daughters, I truly loathe rooted hair because once it reaches that nasty knarly stage the last thing I want to do is pinch the doll in between my legs and hack at it with a brush and comb. I love the simplicity of wig changing. Take off the old hair and put new hair on. Presto. Because life is busy and we want to keep our dolls looking nice. And the longer she looks nice, the longer it will keep your child's attention, the longer you will hang onto it, and that is what extends the doll's life. Because otherwise, your doll ends up at Goodwill and you're buying something else.
So rooted hair. Very easy. Take a pair of hair cutting scissors and cut all the hair off leaving about 1/4" away from the head so you have a nice buzz cut stubble left. Now you can choose at this point to leave it that way and put on a wig over that stubble that is "just for show" meaning you are putting it into a doll cabinet and you can continue to change your doll's look over the course of her life really easily. Or you can choose to remove that 1/4" so that her head is completely smooth and put a silicon cap over it to keep the wig from sliding off and also display it. Or lastly you can remove the 1/4" stubble and then glue a new wig on the head and it's ready for play.
Whatever option you choose, removing that 1/4" stubble can be gone about in different ways. There is a small amount of glue on the end of each of those strands of hair coming up out of that hole. If it's easy to take of your doll's head, you can boil the head, which will loosen the glue and using a pair of tweezers you can reach inside the doll's head and pull the hair out relatively easily. If you aren't up to taking off the head, with a pair of flat pliars you can just yank the hair from the outside of the head one hole at a time until it's all gone. It might sound like a lot of work, but it's strangely satisfying and can easily be done while watching your favorite shows on tv or settling in for the night watching Pride and Predjudice for the millionth time. Once the stubble is gone you can decide whether you want to do the silicon cap option or the glue the wig on option.