I have seen 3 reasons that various menu items have gone off the menu in restaurants. First is that the item isn’t that popular. You mention vegetarian and vegan items, approximately 5% of the US is vegetarian. Now I do like salad, I do like some vegetable offerings, I’ll eat a plain cheese pizza (vegetarian but not vegan), and spaghetti marinara, but more often then not I would prefer some meat. The item may be popular among vegans, but unless the place is specifically a vegan or vegetarian restaurant, most specialize in meat. I think Indian cuisine is one of the few that although it offers meat, the cooks come from a vegetarian life and would be better at doing vegan food. Going away from the vegetarian point, any item that is not economically a plus, gets taken off the meny. Which brings up the second point, sometimes anFish Machine Manufacturers item will stay longer because it is so inexpensive, and easy to make. Even if it only sells a couple of plates a week, it’s not a bother to keep on the menu. If it’s a complicated Tilapia production line recipe, or has unusual ingredients that may cost more then normal ingredients, then it has a higher line where it will be taken off the menu. The final reason is seasonal items. Turkey is cheaper in the fall around Thanksgiving, Pork products are usually less expensive over the winter, although you will rarely find bacon taken completely off a menu. Vegetables are very seasonal especially if you want fresh local grown produce. Fruits are another story because many are imported, and go by the season of where they are, with items like apples being a fall fruit, strawberries late spring early summer, and melons, especially watermelon being a mid summer fruit. They are all available year around, but are fresher, tastier, and cheaper in season. Then you go to fish, and the one restaurant I worked at that had a good fish and seafood menu was almost a catch of the day concept. Now we got weekly deliveries, and the special menu reflected what was running at the time. We did soft shell crabs during the molting season before the shell hardened. We did various fish when it was more available in the mid Atlantic region where I lives. Some like flounder, tilapia, and blue fish (which I never liked, too oily for my taste) were more available year round. We got enough to make it through the weekend and not really any longer. If it was a good price we got it the next week, and so on. So if it’s being taken off the menu, it is probably not selling as much as you think, and even if it is your favorite and people you know like it, it’s not getting ordered. Or it is too expensive to keep on the menu, and with not enough buying it you can’t buy it in bulk or it will go bad. Or it’s out of season. It doesn’t hurt to ask your waiter or the manager or owner, they might know why.