Within the deconstruction project of placing superhero mythology in our real world (versus superheroes existing in the fictional headspace where they can exist as classical idealizations) there are many things that would be different than the comics and other idealized depictions. But the fact that we are not alone in the universe might very well have the deepest impact of all on us psychologically.
Superman kicks off the superhero genre with a story of an ET visitation. Superman is himself a metaphor for what confirmation of the existence of ET means for us. ET has the potential to be good or bad, or a mix of the two. And we all tend to project our hopes and fears onto that, whether we do it consciously or not.
I haven't read Larry Niven's Footfall in a very long time.
But it's not hard to see how an alien race could devastate Earth very quickly if they wanted to do it. At various points, I've seen The Expanse and Starship Troopers sort of discuss these issues as well (big rocks as a type of kinetic energy weapon)
Earth's best defense is getting a city sized platform into orbit. So there is only one practical way to do that. ( Practical in terms of feasibility, not for our environment and not for millions on Earth who would perish based on the total consequences.
The idea that aliens would be smart has always had some push/pull to me. They could be smarter. Or they could be dumb but just have more advanced technology. In essence, what if some aliens "car jacked" some other more advanced aliens and took their space battle cruiser to Earth. And it's just some teenage joyride where they massacre the entire human population because they are bored.
If aliens do show up, and we all find out about it, it's probably going to be fight. OK, well, I'd prefer something different, but when it's time to fight, it's just time to fight.
Something I used to think about when watching Star Trek (i.e. the Enterprise runs into another similar sized space ship), is what if that big ship that is opposite of the Enterprise is really just a single seat fighter from another race?
Can you imagine if the entire Starfleet armada, plus all the Klingons, Romulans and all the rest pooled their ships, and got cooked by a squadron of alien single seat nearly obsolete fighters?
The mistake humans make is thinking "war" with aliens will happen on the same scale. What if they are the size of Smurfs but there are trillions of them that sweep through the Earth like locusts?
I'm not sure I totally buy into the deconstruction arc that's been discussed, but I did really like Man Of Steel.