I used to work for TLK actually. And the place is just so popular. They literally go through thousands of postcards every year. It's quite an unorthadox way of booking a reservation but the noteriety they've received over the years is unprecedented for a restaurant in Maine. Sorry you haven't been able to get in. I recommend checking out The Lost Kitchen tv series on discovery+. I'm sure that'll give you some perspective on how this all works.