But suspended animation, often used in science fiction films with long spaceflights in them, would make a 200-year-long trip seem an awful lot shorter. I don't think it's too unreasonable to assume that a life-form that achieved near-light-speed travel will have also discovered a way to lie dormant during the trip if necessary.
Also, there's no telling how long an alien life-form might live, or how patient they might be. Basing things on human lifetimes and personalities seems a little anthropocentric given that we know practically nothing about alien life.
As long as we're doing away with assumptions, we should also throw out the one that aliens have a desire to propagate and colonize across the universe.
Also, there's no telling how long an alien life-form might live, or how patient they might be. Basing things on human lifetimes and personalities seems a little anthropocentric given that we know practically nothing about alien life.