Writing isn't for everyone as easy, also as much you can critic another writers work, doesn't mean you can actualy also write, imagination, fantasy, creativity are really needed to write in first place, but then it also depends on how well you write, I for one wouldn't know how to write so it would entertain my readers, it also needs a vast knowledge of words, sometimes using synonyms for certain words work better then using the common used words. Another factor many writers often have problems with is writers block, you can create just so much content till your fantasy reached it end or till your reach a point where stories start to look the same as others theirs.