I agree that Rousey seemed fairly arrogant going in, and suffered from believing in her own hype. However, we have to remember that being a villain is just part of her game and what has gotten her so much publicity in/outside of the UFC.
Honestly, what stood out to me most was how out of shape she seemed. I was interested to see how prepped she'd be for the fight, and it was fairly evident how poorly she prepared. Anyone can go all out for 30 seconds, but you could definitely see her fading by the 2-3 minute mark, right around the time the body switches over from anaerobic to aerobic systems. Doesn't help that she kept sprinting after Holm instead of using angles to cut her off.
Not only was she physically unprepared, but her coaches were severely outmatched as well. Rousey goes into every fight with the same strategy: bullrush an opponent and set up a takedown with a few wild and hard shots. Most everyone has stood there and tried to exchange with her, and it's never worked out. Holly needed to keep landing a quality shot or two and move, wearing Rousey out over time. The oblique kicks around her weak knees helped too. I was shocked when Tarvedyan told her she was doing great. Any good coach would have adjusted the game plan and let her know what she needed to correct, but that would require him being a good coach in the first place.
An arrogant attitude, lack of preparation, a slew of yes-men and bad coaches, and the perfect execution of a fight plan by Holm is what culminated into Rousey's loss.