A break out would be where balls are tied up together, you hit into them and move them into a different position. That was the wording of the bet, nothing about a good shot after that. A non-successful break out would be when you miss the cluster, or hit it so soft that they remain tied up. Would I be HAPPY to just hit the balls in a game and get no shot? No, unless I can get a decent safety out of it. In the way the shot was hit, there was some separation of the balls, so the break out was good.
Having a no shot after the break out does not change the fact that the balls were tied up, and then were moved apart.
I think if one argues that the break out failed because there was not good shot afterward, one would also have to argue that in my beak example, you failed the break if you don't pocket a ball and get shape on the next shot, even if you hit it at the speed the bet was for. I don't see anyone that's even a bit reasonable saying that a bet for a 30mph break can be lost if you hit it that fast but no balls drop and you don't have shape. Heck, even if you jump the cue-ball off the table, unless the bet actually stated that you can't foul on the shot, it would be a won bet if you hit 30mph.