Yeah, "decent care" means "kept away from moisture, fire, and bugs."
Such care can be difficult in the long term, but yields results like the beautiful 700 year-old woodwork in this English cathedral. (And of course the comments mention the Buddhist temple Hōryū-ji.)
If we're disregarding proper maintenance, almost anything can be biodegradable too. Steel will easily rust into dust in an alarmingly short period of time, but we have 100-story buildings made of un-rusted steel lasting for a century and maybe centuries more. Compared to cars from 5 years ago rusted into oblivion even while they're still being driven.
In this case I don't think it really matters. No one says "my car is fine, it's just rusting not biodegrading". What matters is that the car is disappearing right before your eyes through natural processes that could have been prevented with normal maintenance.
Wood, when properly taken care of, lasts forever. Steel, when properly taken care of, lasts forever. Each of them will degrade without proper maintenance, and oddly enough they both have basically the same maintenance needs. Keep them dry, otherwise oil them occasionally.
Well, that can be seen as a feature as well. When it's no longer useful and left to its own devices, it will disappear all by itself rather than leaving a pile of toxic waste that someone else has to worry about.
Your second sentence I have no problem with.