Gods are willing to help especially if they feel the sincerity of the request however there are certain limitations because we cannot always get what we want. For example, those limitations include those instances when we want something or someone so badly but such acquisition would ruin and destroy our personality. This kind of situation won't be allowed by the Gods because they only grant wishes that is for the good of people and not for pure selfish intentions. Having to redeem someone who is already dead is such a selfish act by Orpheus and that is maybe the reason why even if he tried everything to get his wife back, he still failed.
