Even the content that made it into the game will never be seen by most users, as most buyers of a video game will never complete your game. But if the ending is not satisfying for those who complete it, they will impact the buying decisions of those who never play through it anyway.
And on top of that:
Before the introduction of Trophies in console games there was no way for game developers to know how far their buyers actually played the game before they stopped and moved on.