there are fewer than 10,000 Vulcans left according to Spock.
Which, if true, is just intellectually lazy on the part of Abrams. First off: we know that Vulcan has had warp technology for about a millennium (thus giving their diaspora considerable reach), second off, we know that they have a number of colonies (which predate the UFP), third off, are they only saying that on all the UFP worlds an in all of Star Fleet there were only 10k Vulcans? Really? The UFP MUST surely be significantly larger than the United State's military (numbering--what?--several million), would that imply that one of the founding members of the UFP sat back and just didn't bother sending its people into the main marital force that protected the Federation?
Just as importantly, it can be easily extrapolated that the Vulcans, being pretty darned smart, would have considered the possibility that a stellar catastrophy could happen and destroy their homeworld (thus, why even bother having colonies?) and would have encoraged their people to settle on many worlds.
What if when the movie ended there were fewer than 10,000 humans left in the galaxy?
In the same vein as my above paragraph, this would have been supremely intellcutally lazy. We know that--pre warp drive--"genetic" humans exist on many worlds outside of Earth. We also know that by the mid 2200's Earth-humanity has spread to numerous colonies (Alpha Centuari, comes to mind, as well as all those "lost" diasporae that were discovered in numerous TNG episodes).
~String