Superman doesn't provide free energy because he believes in the fact that humans should provide for themselves. His purpose is solely to protect humans from forces much more powerful than them such as super powered people or aliens. He knows he could do a lot more, but he refuses to because he doesn't want the world to rely on him all the time, become lazy and not evolve as a society.
The Flash might be fast but he's just a cop. Sure he could transport food to countries that need it, but where will he get that food? He's a middle class citizen.
I don't know much about Storm but I'm pretty sure her powers have limited range and she doesn't have unlimited speed. If she's in New York and there's a hurricane at the other end of the world, then there's no way for her to make it there especially considering that if there are multiple around the world at one moment, how does she prioritize who she helps?
Aquaman is a whole different story though. He isn't a superhero. He's the King of the Sea. When he helps with issues on Earth, it's only because that issue will also affect his kingdom but even then he does hold up tsunamis when he has the chance to do so. Here's a great quote by him in Kingdom Come. "You have hundreds of champions to defend a few landmasses. I protect the other seventy percent of the world... And there's only one of me." Aquaman has no time to protect the human race.
Heroes exist to prevent people or beings from killing the entire planet. They could do many more things, but there's only 24 hours in a day, these people still need to eat, sleep and shit. They're not the people's slaves. While there would be less villains if people didn't struggle for food, there's always people like Joker, or even worse Darkseid, who just want to take it all away because they don't care. Also just look at our world today. The rich just want to get richer while the poor stays poor and gets poorer. The only way to stop that would be to allow the heroes to overthrow governments and that would be an awful idea. See Injustice.