Two of B.o.B's biggest hits were originally meant for Lupe so what happened?

Airplanes and Nothing on you were originally done by Lupe fiasco so what happened? how did B.o.B end up getting them? if Lupe released those 2 singles instead and B.o.B hadnt i think things would of been different? Lupe would of breaked through the mainstream and be a bigger name and B.O.B would be still trying to make a name for himself , i do rate B.o.B (esp no genre mixtape he did) but i do prefer Lupes verses on airplanes