This article is a bit sensational: You have to look at PEDOT:PSS in the context of what it's replacing: Plastics that take hundreds to thousand of years to degrade. That also release much more harmful microplastics that also last hundreds of years.
Compared to that, "more than 8 years" seems pretty fucking good. Especially when you consider that PEDOT:PSS isn't produced at anywhere near the scale that regular circuit boards are (which are made from FR4). In short, PEDOT:PSS is not a serious problem.
Think about it: If stuff made from PEDOT:PSS sticks around for just 8 years, that's better than say, plastic shopping bags which persist for hundreds of years and we manufacture and throw away 5 trillion of those every year.
If everything plastic had the same environment impact as PEDOT:PSS we'd be in a much better situation (environmentally).