The problem with staying where they are and taking the "safe" pick, is it makes them a better team, but it doesn't, in reality, increase their chances at legitimate title contention.
That's why they have to roll the dice. If it doesn't work, they are terrible, which in the NBA, makes you closer to a title than average, unless you are a team that can attract the elite free agents, something the Bulls haven't been able to do. They get used by the elites.