I am pretty such it has been discussed as to why, but 2006 was the last time it was on the West Coast. Otherwise it is East Coast or the Great Lakes/Middle USA area. Maybe the West Coast attendance doesn't stack up, but how could anyone possibly know, since the last one was before ebay took off. Maybe it is time to try the West Coast again.
If you are traveling for the show regardless, I guess it doesn't matter a whole lot if the flight is 2 hrs or 5 hrs, but for those that might consider going via car, these traditional locations are out for most on the West Coast. I think I recall most dealers are coming from those areas too, so I presume that helps drive the decision.
Maybe someday I will make it a point to attend one regardless of where it is held. I guess Chicago might be a good choice, as I have not been to that area of the country other than a short trip to Moline, Il.