I'm beginning to think this is completely different Universe,even before the Narada showed up. There are too many inconsistencies in technology for this just to be a different branch of the timeline from when the Narada shows up.
I think Nero and Spock travelled across not only time but dimensions, too. They went to a parallel universe 2233, one of the countless universes seen in TNG's Parallels. That fixes all continuity problems in one fell swoop!
Different universe, different rules. Khan is white, Chekov was born earlier, Robert April apparently didn't exist, etc. It's a totally different universe.