Okay, for a second, pretend you have the powers of Superman. You can fly around the world in mere minutes, fly, move faster than a speeding bullet, fly, are invulernable, more powerful than a locomotive, fly and show everyone that you practically have the powers of a god. You feed off the energy of our sun, and essentailly spend most of your days helping people all over the world at any given moment. You have a home in the Arctic, you can fly to the moon and back, and have grand adventures with other beings with powers and abilites far beyond those of mortal men. You don't need money, as you don't really need anything like food, slter, clothes, or other materialistic things.
Would you have a day job? Would you deal with the everyday bullshit that the rest of us mere mortals do? The majority of people wouldn't because what would be the point. That's one of the things that actually makes Clark Kent so special. He does, because he thinks himself as a human while everyone else sees him as a god, and who thinks a god has a day job?
That is what makes his disguise work so well. Other heroes are men posing as something more. Some are gods, like Wonder Woman, and she presents herself as such. And Superman comes off similar to Diana, as a god, an alien, an otherworldly being from Krypton, and he doesn't hide his face. That's why his disguise works, because he doesn't wear a mask. The idea of him not wearing a mask is so that people trust him, and because he spends pretty much all his time saving the world and helping humanity, they do trust him.
It is the lack of a mask, the lack of mystery,the scope of his powers, and the confidence and trust of people why people don't think he is Clark Kent even though Clark looks like him, is because Clark Kent is just a man, like everyone else, whereas Superman is a god.
In Action Comics #900, Luthor obtains the powers of a God, and tries to find Superman's most painful memory and Lex is shocked when he finds out that it's the death of Pa Kent. In that moment, he finds out that Clark is Superman and he can't believe it. He always saw Superman as a god who looked down upon humanity, but comes to find out that Superman was as human as everyone else, and it absolutely infuriates Lex. He sees it as a mockery of his intelligence, as he both knows Superman and Clark, and even he could not put two and two together, because to him, like pretty much everyone else, the very idea of Clark Kent defies logic and reason.
That's why I love Superman so much. It's an idea of someone who was raised by kind, loving parents and who just tries to do the right thing with all his abilities.