(The kitchen should always alert wait staff to a potential shortage of a popular dish). Knowing they were running low on a popular entrée I think he might have informed us or queried his guests if they were contemplating something special. If he had not been chatting continuously with the table across from us I think he might have heard our discussing our dinner preferences. We came specifically for the Prime Rib and by the time the waiter finally took our order we were informed they were out of Prime Rib for the evening. and no mention was made of taking order for food.
After being seated we waited for 10 minutes before our drink order was taken.