But it is not the same die, there is a pool of players that can't be picked twice, that reduces by one with every pick, so if the other team misses on a 5-yr starter, it actually increases our chances, that's why it is cumulative. We could just take our own picks for example, if we miss on the first pick, that actually increases our chances of picking a star the next pick because he is still available but there are less overall chances to pick him by the group.
Take this example, there are 3 HoFer quality players in this draft, yet we have no clue who they are, but they will be taken in the first round. The percentage would go up every time a pick is placed that is not one of those 3. That is how the draft works, yet there is a built in probability weighted towards the early picks.