I am not Spock wrote:
It's a total reboot.
The alternate timeline jazz is an olive branch ; so as to not freak out the diehard fans (and they're going ballistic about it, anyway!).
I think Nero and Old Spock travelled not only back in time, but in dimensions as well. The Abramsverse is a parallel universe, in the 2250s. It explains all the apparent continuity hiccups in one fell swoop.
Yes, IRL it's a reboot, but it ties into the old at least as well as any of the other series' and movies (which is to say, a LOT of willing suspension of disbelief is required)