This is why we would have seen robot drones long before alien life
And why all military aircraft will soon be exclusively drones as well.
Those are for kindergarten earthlings and their understanding earthing physics. For every problem there’s been a solution. For cultures thousands of years more advanced than ours, what’s the probability they opened new doors and walked through them?
Perhaps any 'aliens' we might encounter could be advanced avatars and not biological...
It won't be too long before we often see avatars operated remotely by people, imagine the same tech but refined by thousands of years of development...
Package delivery is a good example where people remotely operating avatars makes sense. FedEx avatars with remote operators will be a thing long before autonomous robots can handle the job...