Maybe with what we have at our disposal now it creates the illusion of impossibility? You, nor could I predict what time will bring, or how we will manipulate it for our own purposes. I like to to bear in mind when dealing with exploration. That at one point, not quite as long ago as we would like to think. Sailing around this "cube" of a planet was in impossibility. However, time in this case showed us that it was in fact our undereducated perception that misguided our views. It is important to let go of what you know when analyzing something new. So I am not saying this analogy will ring true in the search for other life and the distances/time it would take to reach. But if you allow your mind to remain in the fish tank that others have built around you. Then your mind will in fact remain in the fish tank that others have built around you.
Basically what I am saying is this question/perception is in need of more input before you can receive the proper output. So instead of jumping to conclusions based on what I am sure in few hundred years from now, will be considered our arcane point of view. You should ask yourself what is the "cube" that we are seeing now that prevents us from achieving our goals and desires. What is our misguided and undereducated perception..Answer this and it would make you an immortal. Your name would be known by everyone for centuries and maybe more. Contradiction of our capability however will bring you no such glory.