Why have many wives in the hereafter - what's the purpose? Well in QM we ended up being married to many different women and when we die we're still sealed to them - so we continue that association. Here's another wild thought....
Why do we have a personal relationship with God. A possible answer is that in one pre earth life dimension we were the only child of God and He and his Wife were able to give us their whole attention while they raised us from intelligence to a spirit. It's possible that when we die, that we go back into that same dimension and continue to live with or Heavenly Parents on a personal one-on-one level of existence.
Also... I think the move Ground Hog Day resonates with many people because they kind of feel that this earth life is a time to learn and "get it right." GHD is a great message, and deserves to further explored in another movie,