I'm not so sure. It sounds good in theory, but really most people are going to succeed, and most of the people who fail will reload, so for whose benefit would these additional paths be made? This is a huge amount of extra content and I really don't think it would be worth it.
Maybe they could design the odd quest to branch in this way, but only the odd one. They would also need to be very difficult in order to make sure there's actually a decent chance of players seeing this content.