If you have a specific trigger you may want to research the movie ahead of time for content. Resources like does the dog die help. Depending on your exact needs you may be able to use other tactics like watching with a friend.

And if people don't want a challenging game they can research beforehand and decide not to play it. Or they can get a friend to help or they can find mods for the game or they can watch a playthrough. But with games instead of working around the vision (like you've suggested with movies) we decide that developers should compromise their vision.

Difficulty is tuneable after the fact. The developer had to make choices about the numbers and implementing them in a way they can be scaled isn’t necessarily more work. Lazy scale the number difficulties are still more accessible than single difficulty.

I think you're mixing up difficulty for the sake of difficulty with difficulty for the purpose of something else. You can tune difficulty for the sake of difficulty and I don't an issue there. I don't think you can tune difficulty that's designed to evoke a specific feeling or guide the player in a specific way. Take the Asylum demon from Dark Souls. It's supposed to be near-impossible to beat the first time you see it because the game is telling you to do something different. If you turn the difficulty down and it becomes beatable then you're actually skipping the rest of the tutorial the game designed for you. And of course environmental difficulties are even harder to tune. You can make Sens Fortress deal less damage but if you can't avoid the traps you're still going to end up knocked off and have to start again.