Comic Book Death why? If you are going to kill off a character then make sure he stays dead.
Good God...
You're forgetting (or are simply ignorant of the fact), that cape comics are an almost endless stream of endless endlessness. By which I mean, that they are going to go on forever. So unless a reboot happens (DURR DC), if they started killing off characters for good... they would have to come up with completely new ones, not to mention "shake up" the status quo.
And that's a [tornado fang]ing impossibility.
Because:
1. Iron Man, Spiderman and other characters like these cannot die (for long) because their [parasitic bomb] (no matter how [parasitic bomb]) sells.
2. Shaking up Status Quo? AHAHAHAHAHA! Yeah right, maybe in a different dimension.
3. THEY ARE ALL LAZY ASSHOLES!
That's (more or less) how it looks, though I might be a bit wrong about something.
Keep in mind this state of affairs is usually present only in cape comics.
Besides, you're talking like it never happens in manga/anime. Pfft.