You think because the computer is in California that it only knows how to drive in California? Maybe you should learn the first thing about something before spreading FUD about it?
It wouldn’t matter if the training computer were on the moon. Training data is collected by Tesla owners all across the country including the Eastern United States. Regardless of how well you think it can drive, it can drive equally well in New England as it can in California. And there may be an unequal number of Tesla’s on each coast but that’s irrelevant.