My point is, the MCU has established years of internal chronology which differs from our own world, even if by less than Star Trek. This means that the stories you can tell within the MCU are now somewhat constrained
Which is true of many fictional universes, so I don't see the issue.
I didn't say it was a deal-breaker, but there were cases (like in Secret Invasion, and to a lesser extent, Eternals) where it did kind of stretch credulity.
Yes, sometimes it can. No doubt
Secret Invasion suffered badly by not including any major superheroes other than Fake Rhodey. But that's a critique of a single work. It doesn't translate to a systemic failure of the whole franchise. It's an issue in any shared hero universe, as I said. Why doesn't Superman pop over to Gotham on his lunch hour and clean up the city? Because Batman stories need Batman to be the hero.
As I keep stressing, the continuity between series is supposed to be secondary to the needs of the individual series. It's there to support and supplement them, and like any other story device in fiction, you set it aside if it gets in the way of the story you need to tell. Continuity exists to serve story, not the other way around. And yeah, sometimes it doesn't make sense, but it doesn't make sense that Superman can fly, or that Batman is still able to fight at peak level after all the cumulative injuries he's received. Stories rely on the audience's willing suspension of disbelief.
But, that's what Marvel did with Thanos. He murked Loki at the beginning of Infinity War exactly to establish he was a big enough threat to take out the antagonist of the first Avengers movie - alone.
I never said that device couldn't work. What I object to is the facile notion that it's the
only possible way to establish a villain's threat.
I'd also note that it's a very common trope in fiction to have a central character - often the older mentor figure - killed by the antagonist in order to show the level of threat.
"Common" doesn't mean "right." Often it just means that a lot of storytellers don't try hard enough to find alternatives. Personally, I find that relying on character death to make a story point is all too often a cheap shortcut and a substitute for more creative solutions.
Not every sacrifice has to be the "ultimate" one. But when heroes give up something due to their actions - even if it's something as simple as a friendship irrevocably broken - it makes for a much more memorable ending.
It
can. Doesn't mean it absolutely has to in every case. I mean, why the hell would you want a tragic ending in an Ant-Man movie? It's like the old saw about Shakespeare plays. You know it's a tragedy if everyone dies at the end, and it's a comedy if everyone gets married at the end. Comedy entails happy endings, usually. Unless it's a dark comedy, which Ant-Man isn't.