Has McBeth won because he shoots lights-out in the later rounds, or because he doesn't have a bad round? (I have no idea; I don't follow the top pros that close).
It seems that a consistently-excellent player, in a field of less consistent players, would get a similar result. In the early rounds, some of the field would shoot really hot and put him behind, while others would have weak rounds early. Some would have weak rounds in the middle of the competition. And some would have their weak rounds late, giving the impression that the consistently-excellent player is pushing past them.
I'm not saying that's the case, because I don't care enough to look it up or analyze the results. In theory, however, it would be a rationale for more rounds.
On the other hand, making each shot and each round more important would be a rationale for fewer rounds. In a shorter tournament there's less time to rally, thus more pressure to be tops from the very first throw.