There Are People Superman Can't Save (and That's a Good Thing)
Batman has Gotham, the Flash has Central and Keystone City, and Martian Manhunter has Middleton. While Superman may live in Metropolis, he is America's hero. He has a lot more ground to cover, and also divides his time hanging out on other continents (wintering in the Fortress of Solitude, etc.). Now, a man who can travel faster than a speeding bullet still can't be everywhere at once, which suggests that somewhere there are people dying in warehouse explosions and mass murders and roofing accidents every single day because he's busy flirting with Lois Lane or fighting Lex Luthor. For every person he saves, there are hundreds more, some of them children, taking their last breath while staring hopefully at empty skies.
Superman can't help but set a precedent he can never live up to. From the first time he stopped a bridge from collapsing or diverted a tornado from a town, he instilled a false hope among Americans. That means that every day, even if he never bothered to put on glasses and go to work again at The Daily Planet, Superman is still letting down hundreds if not thousands of people.
Somewhere, someone left an infant in the car with the windows rolled up. Superman has to decide which life is more valuable.
Add on top of that everyone who is dying of societal problems that are beyond his capacity to fix, and suddenly a really interesting portrait of Superman starts to emerge. Nearly every writer who has ever tackled a Superman story arc has tried to test the limits of his powers by pitting him against an alien being who's even stronger and more super, but they are completely ignoring the potential all around them for an engaging narrative about Superman struggling and failing to help everyone all at once from broad, systemic issues.
He stands for truth, justice, and the American way, but justice and the American way don't always see eye to eye. There's no way Superman can stop homelessness, disease, teen suicide, or domestic abuse. How could he? One of his powers isn't lobbying local politicians. That's why the most interesting Superman arc isn't about Lex Luthor building a secret island or bad guys coming from another galaxy to wipe out civilization. It's about a country of people who live at the edge of Superman's capacity to help, but because of that part in his super brain that wants to protect humanity at all costs, he nearly destroys himself trying. It wouldn't be about Superman, it would be about the people struggling and dying in a world where he exists, but he still can't save everyone. Give me that movie and I would watch it over and over just to see the greatest version of a human driven to the breaking point like an engine with no oil. Superman could be our test-drive hero. I would watch the hell out of that.