Wood didn't rot in the carboniferous era. It used to build up in dense layers that became our modern coal veins.

At some point microorganisms evolved to exploit that vast resource. Now coal can no longer generate naturally and we have to keep wood structures dry or painted lest they be reclaimed by the Eafth.

I don't know if there's any reason it couldn't happen to plastics. We've created the niche already, how long until something exploits it?

Rust is not caused by a living organism but fine. There's another good solution: don't use plastic. Also, we don't need personal cars

Yeah it just destroy the purpose of plastic

Well there is a simple remedy, and it is the same like for rust. Keep it dry. All microbial live needs water just as much as larger liveforms. If it is dry it can't spoil, even if there is microorganisms on it. They might be alive, but they'll be in stasis without sufficent accessible water. accessibility is also important here. E.g. salty water or water with high amounts of sugar are not useful to most microorganisms.