Many of them pay to put macroplastics in their boobs, so not very likely.

Silicone is not actually plastic and definitely don't break down into microplastics (if they break down at all). There's varieties leeching suspicious stuff but for some applications the nice ones might actually be the solution of the future, say, for seals for glass jars and stuff. Rubber isn't better just because it grows on trees, rubber tyres are one of the main sources of microplastics.