The point he's making isn't really that it's utterly impossible to get to an exoplanet though; it's that it would be completely impractical to migrate there en

The point he's making isn't really that it's utterly impossible to get to an exoplanet though; it's that it would be completely impractical to migrate there en masse since it would take so long (if indeed we could get there at all), so we need to take care of the planet we have.