^ There's certainly room for error, but Memory Beta says that the Axanar battle took place in 2251, which would make it pre-ST XI but post-Nero. Thus it would fall within the Abramsverse. So it could turn out completely different this time around. Including Garth's fate.
Isn't Garth supposed to be much older than Kirk?
They seriously "agebent" Zephram Cochrane when they recast him for ST:FC. Nobody complained.
It was suggested that Cochrane looked the way he did because of radiation poisoning, and also because he was a drunk. Either is a sufficient explanation, really.