What's actually happening to the plastic? It can't be coming off my clothes in the washing machine at any profound rate, yet remain good as new for years. If I

What's actually happening to the plastic? It can't be coming off my clothes in the washing machine at any profound rate, yet remain good as new for years. If I dispose of something in my locale, it goes to a sanitary landfill and will never see air, water, or sunlight. I'm oblivious to fashion, much less fast fashion ;-) Is there an ecologically responsible way to use synthetic clothing? Natural materials are not without their environmental impact either.