The bad ending is the result of the choice you made, these kind of games doesn't really work without a clear "correct" path, otherwise you just finish the game after the choice that led to a bad end. It's an ending that you found through your choices. What would you suggest they do? In the case of this game, and it's a very specific case, I guess they could make all the bad endings just start the time loop again, but that would only work for this game specifically because of the concept.