Real Life: There are some very talented, heroic people out there in the world (the awesome reaction of the Boston Police to the Marathon bombings stands out as a recent example). Still, nobody has figured out how to turn into a massive green monster or use a Vibranium shield to block a god's hammer strike.
Of course, we're not about to criticize a superhero movie for having superheroes. In fact, we think the Marvel Universe is on to something with its super-strong characters, like the Cap and Hulk. Though super-strenth will probably never be achieved with serums, genetic engineering may well yield much stronger human individuals in the future. In fact, gene manipulation could also make humans smarter, healthier, more resistant to pain, more...superhuman, in short. There is a vibrant ethical debate on this subject in the 21st Century, since many disagree about whether we should be designing humans the same way we design cars. What do you think? Would you mess with your genetics if it meant you could Hulk out whenever you wanted?