Exactly.
In any kind of programming design, OO or otherwise, the goal is to find a good representation for your purposes. My point is that there often isn't an "obviously natural" representation just waiting to be noticed, and existing OO systems have to stop at partially expressing the full conceptualization that the programmer might have of the problem domain.
OO is one toolkit for producing useful representations. It is a useful one (else it would not have become so popular), but it is not the only one, and it is not always the right one.