Another way to save Emma
I get the need for Emma to die in every iteration/universe for the time machine to be built. However, I am still a bit confused about the vision shown to Alex by the uber Morlock. Why couldn't Alex be happily married to Emma and not have built the time machine as shown in the vision? Why was building the time machine such an important event that it could not be changed? (when we could delay even the judgement day!)
If we consider the paradox that it causes by saving Emma and endangering the existence of the very vessel that Alex uses to save Emma, then its fair that Emma dies and we have the cause-effect established as Emma's death=time machine. However, how about if Alex were to destroy the time machine as soon as he goes back in the past? Since there is no time machine in this universe, Emma's death doesn't need to happen and he could live with her happily in that universe.