Huh? BitD cannot be characterized as collaboratively decided outcome. Players propose moves their PC will make and the GM considers the fiction and proposes a position and effect, basically the risk and reward based on factors like relative tier, scale, quality and fictional position. The players can then elaborate by using inventory, assistance, leadership, special abilities, pushing, or accepting a devil's bargain as a consequence. Dice are then tossed. This is usually repeated several times per combat. There may also be resistance rolls.Like S&V, you mean? Careful.
I'm not sure what fair means here. D&D nowadays generally assumes combat is winnable. BitD probably does too, most of the time though exactly what that means may be a bit different.None of that counters the point that it's still a cooperative experience. The dice can't create fairness in an encounter that was designed without it. The dice are there is provide uncertainty and therefore tension in an otherwise fair encounter. That's the whole point of the thread.