Maybe because in this universe there are no Time Lords? Maybe the laws of time are different? I mean, there are people around here with similar appearances, or people seem to dream of various versions of themselves. At any rate, it would be a fascinating project to undertake and find out the whys and hows.
Because even without the multiple TARDISes, Orange County should be one giant hole in the fabric of the universe, and it does not seem to be one. At least not in the way we are used to.