...Most of the time no one died in a gladiator fight
If you were to watch Hollywood you would be left with the impression that every gladiator fight ended in the death of the loser. We’ve all seen it. The triumphant gladiator looms over his vanquished foe and waits for the decision of the Emperor. Listening to the crowd, the Emperor pauses before dramatically putting his thumb down, at which the victor finishes off his opponent to the roar of the crowd.
Without even going into the questionable thumbs down gesture, the overriding problem with this is that actually only a small proportion of gladiator fights ended in death. It is true that the fate of the defeated was left to the ambitious politician who put on the games, but, as with all entertainment today, it was also a business; gladiators were quite an investment. Gladiators were far from amateurs. Training a good quality fighter could take years of training, feeding and clothing them from their owners, not to mention the time and fights required to gain a reputation. Therefore, summarily executing them meant an instantaneous wiping out of this investment; as such the gladiator’s trainer would often receive compensation from the show’s sponsor were they to be killed.
Naturally this is not to say that gladiator fights were not a dangerous business. Death could come either in the course of the fight or as a result of the patron's decision. However, Professor Mary Beard in her book Pompeii: the life of a Roman Town puts the chances of a bout resulting in a death, by either route, somewhere around 13%. Such a rate means that a gladiator's life expectancy was rather short, with the average age of those recorded with tombstones being in their late twenties. However, the fact remains, most of the time that Hollywood scene has it wrong. The vanquished gladiator was far more likely to be spared than skewered.