You only live once

When it comes to its characters, particularly its heroes, Marvel doesn't like taking any chances. If the studio believes they have found the perfect actor for the perfect character, it isn't going to let it go too soon. This is the reason why Robert Downey Jr. was able to renegotiate his contract several times, making $80 million this year alone with one single movie. This is also the reason why Loki has been brought back "“ after all, it was all just because of Tom Hiddleston's charisma.
So even if one such character appears to bite the bullet, the biggest chances are that he will be brought back. We aren't going to bring Coulson in the discussion, since he is dead for the MCU (as Whedon stated). However, Nick Fury falls in the same category, just like Loki himself, or even Quicksilver (about whom we don't really know whether he will be brought back or not).
Apparently killing someone simply doesn't cut it. There is no real threat any longer. For example, Coulson was one of the characters who brought the movies together during the Phase I. His death (a rather heroic one) showed us that Loki meant business "“ making a show on TV around his character diminishes the importance of his death.
The same goes for Nick Fury. Why is the Winter Soldier seen as the best assassin, if we do not actually see him assassinating anybody at all? Sure enough, there is the cannon fodder "“ but nothing else.
So maybe Marvel should consider letting its dead characters stay dead. Live and let die and not You only live twice.
As far as Quicksilver is concerned, we might believe that he is dead "“ though we don't know how a speedster can be killed with simple bullets. But we do believe that Marvel will bring him back "“ after all, Age of Ultron presented the technology which can do that.
Sure, these are movies based on comics "“ and in comics nobody really stays dead. But comics have been about for decades now, while the Marvel Cinematic Universe roughly has one.
Check out the second page too, just for fun!
