[dsign]

There is so much we don't know. But I would happily engage in speculation:

- Without needing to make it to the closest star, we have big problems here. If we solve those problems before we leave our solar system, we may be changed beyond recognition. We may not be biological any longer, for example, or at least not forcibly so, and traveling as solid matter may seem silly to our future descendants.

- We don't understand well enough the nature of reality. For all we know, our machines and organisms made of atoms and molecules may be, by far, more inefficient and wasteful than an equivalent process at some other layer or scale. Like somebody who discovers themselves living inside a match box in a forgotten attic, we may decide to move to the more spacious main floor of the castle.

- A variation of the above: maybe space-time itself is something we use inefficiently. It could be that a way to stop being troubled by the slow speed of light is by lowering our own "life" speed, increasing our volume to span entire solar systems, and decrease our density so much that your ancestors would confuse us with sparse interstellar matter. Or, at the opposite end, it could be that we find a way to move our entire future civilization to a cubic centimeter of space and a few microseconds that feel like eons.