Firstly, the argument about the market for casual women's apparel is rooted in the assumption that the market is saturated and can't take any other styles. However, the author provides no evidence to support this key assumption.
Secondly, the author takes a flipping position by expecting that DKLA is going to fail. This position ignores the possibility that the company to create a new styles that can generate profit for the company by increasing the sales.
Therefore, to make this argument persuasive, the author needs to present specific