Not a believer of the 'imagine if he stayed he would've banged them in' there's too many variables as when players leave and they start performing. The 'rejection' itself could be a factor into his output, drop in division and therefore level all will play a part.
However, I always look to see how he's getting on and what if he did stay.
I expect a bottom - mid table Champ club or even one of the relegated sides to move for him in the summer.