Same reason an NBA team will draft someone who isn't ready be a starter averaging a double double. If I believe the team is elite and that the potential is there, there's potential for such an asymmetric outcome that it's a worthwhile bet.
I don't know the NBA that well but in NHL you would draft someone with high stats in the minor leagues, knowing they will develop (physically and mentally) into someone who can achieve the same stats at a higher level. The game is the same but the parameters are larger. It takes time to work out at the gym, make quicker decisions, cleanup some weakness. There are many other factors like how their strengths will play into the teams structure, etc.
Is this the model you would apply? What are the parameters that are key to founders beneath the idea itself?