If their resources cost more to harvest than what it costs to send a rocket back out, it’s a dud. Sending humans, lifeforms evolved for life on Earth, is stupid beyond belief. You send life engineered to what best fits the environment, and if your society can’t cope with that fact because it is too species-centric, you get nothing. Never mind what actual interstellar travel requires, which is coping with timescales and hibernation states completely alien to us. Because a lot of what space requires involves a lot of what we can’t cope with, it is far more likely that it will belong to our predecessors.