Some people do draw their hair in Adobe. It's not an easy process to get good results, but we do have a few masters here for hair. Dalinese and Stormi come to mind. Most people prefer using 3d models for hair so they can use it over and over again. Kozaburo is the undesputed master of hair and has several free models, but hmann and Vairesh (among others) are also excellent at hair and have several models available for purchase.