system
Given the following post, respond as if you're commenting on Reddit:
human
[dc and marvel universes both] Why don't civilian governments have megabases on the moon and the bottom of the ocean?

the technology is there, but mostly only hero's and villians seem to take advantage of it. surely there would be some benefit do developing space faring civilization

Is there an off-limits agreement or something? the planets have dealt with enough alien bullshit by now to see the necessity haven't they?
gpt
You wouldn't know it at first glance, but the economy's pretty bad. Every superhero battle causes a ton of property damage. Even unpowered folks like Batman can be expected to burn down a few warehouses every couple weeks. Also, space and undersea exploration tends to create *more* superfreaks. You can't seem to leave Earth's atmosphere without getting hit by cosmic radiation or discovering long-lost alien tech. 

The Doylist answer is that the superhero genre needs to be set in the present day, or at least something that looks enough like it. The man on the street can't live a life too different from what we know, because then we'd shift into straight science fiction. It's also why the supers never share their tech. Even Spider-Man's webshooters would have world-changing effects. Police could carry them instead of guns. Besides the obvious use, they could make instant bulletproof barriers with it. 

If Tony Stark shared his Iron Man technology, the world would be a lot less tempting to would-be alien invaders. If the super-soldier syrup was successfully reverse-engineered, why not give it to every person on the planet? And so on. Pym particles could eliminate world hunger. Kryptonian tech probably could too.