I think you have me confused with another poster man.
That aside, that is just wrong on your part. First, second, third level and even the villains on occasion will put themselves in harms way as some sort of sacrifice, whether its to save the world or just buy much needed time. Not all of them can be the super, ultra top hero however. A story where every hero is as powerful as the next lacks the depth you so desperately crave in the individual. Everyone being Superman makes the small fights mean next to nothing, same with sacrifices.
Rider wasn't that much of a joke either. OPM universe is pretty well explained. There are levels of heroes and Rider is on the lowest rung power wise. He takes care of street level shit, the cat out a tree sort of "hero".
This act however, of a street level hero stepping up to the plate when he absolutely has to and no one else will is what upgrade him from "hero" to hero.
Writing wise, those characters stalling create tension. It helps show that a hero isn't just having the costume and the powers, it's about the attitude and willpower which Rider has. Saying a character isn't worth your attention is going to make for a pretty shitty read as almost every comic, manga, book and film has those characters. Strip away all of those and suddenly Superman has no Jimmy or smaller JL members, it's just him, the big hitters, the villains and the victims and that makes for a pretty empty and ultimately shit universe to read about.