Most people attending Disneyland aren't exactly close enough to just drive and eat at Yamabuki. And if you haven't noticed the neighborhoods surrounding the Disneyland resort aren't exactly OC's finest either.
Majority of people there who WOULD eat at Yamabuki either don't know about it or are too busy enjoying their day at the theme parks to go through that kind of trouble for a meal. There are people who wouldn't even go across to Disneyland from DCA to eat if that's where they are.
And it sure doesn't help that the Paradise Pier walkway to the hotel hasn't been accessible either.
No matter how you look at it, it's quite a walk. And actually, if you're in Tomorrowland, that's the best spot to be in to go to Yamabuki -- just hop on the monorail and then walk past the AMC Theater and Disneyland Hotel, cross the driveway to Paradise Pier Hotel.
I'm glad to hear that you're going as many times as you can though. I wonder if there is a way to save it if enough people visit or write.