Technically, there's nothing in the film to suggest that the flashback, 24th-century portions of the film take place in the same timeline as the one Trek's been exploring for the last quarter-decade or so, and a fair amount that would suggest otherwise.
That's an interesting interpratation, but it's not what was intended. Nimoy himself is the anchor-point that links new trek with the old. His presence is to assure us that, yes, this really is the Spock we knew. That's certainly how he played it, and it's why Abrams was so strongly intent on bringing Nimoy aboard.