I don't want to fly on an airline with profit margins so slim. If a few hundred dollars one way or another is all that matters, I don't want to think about the decisions going on behind the scenes. These are extraordinarily expensive machines filled with hundreds of very human humans. You need more room for contingencies. I'd rather pay a few dollars more if that meant flying on a plane that wasn't constantly skirting the edge of profitability, one where employees have room to take reasonable and safe decisions.