Indeed not. Not everything is about last minute decision. But a many people know enough to do things just to be on the safe side, especially seasoned gamers. I think not a few end up mixing the potion anyway and decide what to do with it later. The game even leave the choice of using the key item you obtained until the last minute. That leaves room for players to make the last minute decision to throw items into the right place. And that choice alone affects the outcome. Faravid's trying to suggest a choice that make an irreversible turn somewhere in the middle of the game, and whatever follows, including the endings are consequential. A choice that you have to go back to the middle of the game then play it again from there to change, instead of loading the last save to change.
Also, the choices in this game are clearly visible - figuratively. Throw it in or not. Mix it or not. It's not that subtle. No offense.
I'll give a little example from another game to make my point. Silent Hill 2. There are six endings, IIRC, and each of them truly takes what you do throughout the game into account. If you treat yourself well, don't dwell in your past, and stay healthy throughout the game, you get an ending that represents moving on. If you treat yourself badly, heal little, take lots of damage, look at suicidal stuff, you end up doing bad things on yourself in the end. If you interact well with a character that represents your past, listen to her, protect her, take her suggestions, stay with her, even not bumping into her throughout the game
, you end up with her. Each factor that affects the ending is very small, unseen, and many are truly affected by your unconscious decision, or close enough. More importantly, all factors are collected throughout the game and can only be changed significantly by almost starting over. Factors that prevents last minute decisions. That's what he's talking about. And that adds a very, very great replay value.
Justine is also a great example for the choices that affect the game. Save how many, and whom. The choices are still a bit obvious, though, but at least you can't just load the last save to change those factors. (If
you could save.)
An upside of getting all endings easily is that it's easy. Me like that.
I don't have to go through all that again to get them all. But that means beating the game only once and then... 'Now what?'
Edit: I'm not saying that the game has to be this way. I wouldn't mind an ending like Penumbra: Black Plague. But if it's multiple endings, Faravid's suggestion is a good idea, and I was just trying to clarify it.