DO you fabrics/materials help solve a problem or make you unique? Those are to very important questions. Is it one, or the other, or both? We've all seen it, you can get a copy of a $900 purse on Canal Street for $80 (which is a great deal if you're into it). Sure, you can build a business behind leveraging the 'Supply & Demand' idea in the market but you aren't really creating an innovative product. You're just basically copying something.
Remember, at the core of your idea, you should be solving a problem. You can absolutely solve that problem by having an innovating idea, but you can also achieve that by taking a current product and innovating it using new fabrics or materials. By making these decisions, you are setting yourself up for success.
There's a great example of this with the 'Ove Glove', a rework of the classic oven mitt that's built to withstand heats of 540 degrees. They've taken a current idea and innovated the fabric. Brillant.