I don't think that works as an analogy. In a restaurant, one orders something that already exists (the food), which is then delivered. In the case of George RR Martin, it can't be ordered because it doesn't exist. The only way one can compare this to a restaurant situation is if one orders one of his existing books from a retailer like Amazon and it doesn't turn up.

Ultimately, expressing disappointment that an author won't pull their finger out is one thing (and I sympathise), but seriously believing they "owe" the reader something is delusional.