This article speaks to the lack of infrastructure for biodegradable plastics. While this article discussions plastics, and not textiles, there are a lot of similarities between the two in limitations around biodegradability.
Read The Guardian’s article: Plastic alternatives may worsen marine pollution, MPs warn
”Compostable and biodegradable plastics could add to marine pollution because there is no infrastructure in place to make sure they break down correctly, a committee of MPs has warned.”