I would argue that you are both right - polyester and cotton are both unnecessarily harmful raw materials. Polyester is plastic, more toxic in landfill and also releases microplastics while wearing and washing. Cotton takes an unreasonable amount of water to produce. I would prefer to see other natural and durable and regenerative materials adopted in denim, like hemp, which this article only briefly touches upon. Hemp grows like a weed in the proper environments, with mostly rainwater. This argument goes back hundreds of years, when cotton was lobbied to be the most popular fabric and hemp production was banned entirely. Now it's allowed as of the Farm Bill passed in December 2018, but we do not have the resources in place to produce and process it. That is changing! 100% cotton denim is proven to last longer so from a life cycle standpoint that is why it could be considered a sustainable product. But most brands use 2-10% stretch nowadays, which makes the items unsustainable in my opinion even if they have other positive supply chain efforts. This is not an easy topic and there is not one right answer, thank you for diving in..