Well, if they obeyed real-world physics, they wouldn’t be super-powers. All of this stuff is fantasy, none of it would work at all in real life.
And I think super-power depictions are typically as consistent as the performance of athletes? Why is it that, on one day, a person can break a world record, and the next day they can’t seem to get anywhere near as close? Super-powers and the performance of super heroes are like that as well.