I reckon you can explain a lot of stuff that happened quite easily with the simple assumption that people assume that the dimensions diverged with the Kelvin Disaster. It didn't, you just need to think carefully about it. I apologise if this has already been postulated in the thread. Prime-verse: In the timeline that we're familiar with, things proceed as we have witnessed them. Captain Picard assumes command of the Enterprise E, fights in the Battle of Sector 001 - travels BACK in time to 2063 and helps Cochrane make his first warp flight. At a later point, Romulus is destroyed catalysing the events in STXI. Abrams-verse: As we know, Nero encounters and destroys the Kelvin which is the assumed divergence point for the universe. I put forward to you that the reason that the universe is already so radically different (the arrowhead insignia being used on the Kelvin and the ships looking so radically different, to give two examples) is that, in the future of the Abrams-verse, the events of the TNG unfold radically different, Picard doesn't necessarily take command of the Enterprise-E, the Battle of Sector 001 doesn't necessarily take place and Picard doesn't necessarily help Cochrane make his first warp flight - or events are radically altered. Thus, events in the universe alter from 2063 onwards (and not from the middle of the twenty third century as generally postulated) with, for example, Cochrane suggesting the arrowhead symbol he glimpsed on Abrams-Picard as the insignia of the Starfleet that comes into existence much later (history would record that it was Cochrane who came up with the idea, but wouldn't say where he got the idea from). The ships look massively different from this simple catalyst too.