The whole situation with I Am Legend 2 (yes it's real) is convoluted as can be. Apparently the true ending of the first movie can only be seen on the Director's Cut of the movie, what we saw in the theatrical version was the "alternate" ending
they're probably using that ending because i) it's more accurate to the source material, the novel of the same name by richard matheson, 2) it's more accurate to the original vision of director francis lawrence and screenwriters akiva goldsman and mark protosevich, and c) it's just a better ending
