Death is a minor annoyance in any superhero universe. Guys like Nick Fury and Jim Gordon get emotional sendoffs and then come back in the same fucking movie. The heroic "death" of Agent Coulson was supposed to be the entire reason the Avengers came together, then he got a whole spinoff TV show of his own. (The Avengers are apparently so bitter about this deception that they now refuse to even speak his name.) And those are side characters -- who was fooled for even the two minutes we were supposed to think Bruce Wayne was dead at the end of Dark Knight Rises? Or that Superman's supposed death in Dawn Of Justice would last through the prologue of the next movie?
Look, we get it. Even though real stakes are kind of important in storytelling, no child wants to buy an action figure set featuring Bruce Wayne joining his parents in Hell. But we've reached a point where screenwriters don't even try to pretend these characters are mortal, and the characters themselves seem to know it. That's how you end up with movies like Captian America: Civil War, wherein various elite marksmen, genetically enhanced super-soldiers, and a scarlet witch settle their differences with the most casual and glib battle in the history of violence. A bunch of children playing out that scene on a playground would feel it more.
It really does come off like Peter Parker knows he is safe not because he possesses the natural hand-to-hand combat abilities of an average spider, but because he knows there are action figures to sell. As for a character like the Hulk, the films make it clear he couldn't die even if he wanted to (as in he seriously wanted to, but couldn't). But ...
Let's Talk About The Time They Killed Hulk And He Fucking Stayed Dead
This, naturally, takes us to the 1977-1982 Incredible Hulk TV series. Before they could watch him star in big-budget movies every other year, this was how Hulk fans had to get their fix. Every episode saw David/Bruce Banner solve crimes, save lives, and inevitably turn into a rampaging rage monster, all while trudging toward finally getting his Hulkamania under control and clearing his name of murder. Fans connected with Banner's plight throughout the years, and hoped that he'd one day find a cure so he could enjoy a normal life, or at least stop having to replace his shirt every day. (Fun fact: The network changed his name from Bruce to David because Bruce used to be thought of as a stereotypically "gay" name, and they couldn't have that. We've come a long way, folks.)