Honestly I think I'm one of the few who absolutely hate that something/someone has to die in order for my entertainment to "mean" something. Or that if a character's "use" is up then they need to go.
Outside of the MCU going into the shitter my other reason for not continuing to watch was that the actual characters I gave a damn about (Cap and Tony) weren't going to be there going forward.
And it's not just the MCU too but other stories/comics that have done this.