This already happened with C8 -> C6 which bioaccumulates in water rather than in the physical form. Fundamentally, making something immune to water requires als

This already happened with C8 -> C6 which bioaccumulates in water rather than in the physical form. Fundamentally, making something immune to water requires also making it immune to the normal way that things break down in the environment. So the performance qualities are really the thing we may need to phase out, but there are applications (e.g. in surgery instruments) that are more or less essential.