But needlessly bombarding it with artificial chemicals surely has some kind of threshold over which adaptation mostly fails, equilibria get destroyed and the system becomes indeed instable.

> ... as long as it isn't disrupting ecosystems.

Problem is, who can reliably tell when it'll be too much?

IMO not worth risking "everything" for some added convenience of "ingenious" food packaging.

The point is that from a human perspective, and from the perspective of most multicellular organisms, plastics discarded into the environment are a really bad thing for our health.

Since all life forms on earth rely heavily on water as solvent (being present ideally all the time), those 'invasive' bacteria won't have that much of an effect on humanity's habits IMHO, since regularly removing the water easily keeps their impact low.

Fungi might play an important role in decomposition of plastics as well, since they have advantages over bacteria that may be relevant for decomposition of plastics in the same way in which they are for decomposing wood. (Which is difficult for bacteria)