That really depends on the author's motives. A lot can be learned by creating "yet another X". Not everyone thinks the same way and creating a framework from sc

That really depends on the author's motives. A lot can be learned by creating "yet another X". Not everyone thinks the same way and creating a framework from scratch gives the author an opportunity to get a deeper understanding for similar concepts and possibly a chance to invent a whole new approach. So many great things would not exist if everyone just settled to use or contribute to existing projects with similar goals to their own.