Your second paragraph could be summed up as: we chose the destination years ago, so there’s no point changing course.

Which makes perfect sense when you consider that there's a deadline, we've gone a very long way in one direction and going all the way back to take another route would guarantee missing that deadline.

It's like you're taking your ship from China to Rotterdam, you're past the Suez canal, in the Mediterranean and now you decide to turn around and go around Africa after all. It really would be idiotic.