I have been a consultant to many restaurants and been heavily involved in several. What I have observed is that restaurant menus and food changes often depend on the incoming flow of customers.
One of the sad examples was a restaurant in North Beach, San Francisco, that opened to glowing reviews and, in my personal opinion, had a wonderful menu and exciting food. Over time, I watched the chef pay attention to the food that was left on the plate as it returned to the kitchen. The consequence was that the restaurant went straight downhill for a year until it was no longer a top destination restaurant.
What was happening was that people who were customers with refined taste buds would come to the restaurant with some of their friends and tourists would also go to restaurant because of the good reviews. The people with refined tastes that could appreciate the chef's great work were only about one out of 10 or one out of 15 people. The chef was looking at all of the plates, with unfinished food, that the non-appreciative people were leaving behind. The chef was inadvertently targeting his food at the wrong audience. He dropped all of the interesting food, such as asparagus, artichokes, fried olives and esoteric sauces.
He ended up with only tourists and people with macaroni-n-cheese tastes. For those people pizza is sufficient and the restaurant could not compete with the successful pizzerias in the neighborhood.
Most top-flight restaurants pay attention to the chef’s palate and ignore customers who don’t appreciate it.
Other restaurants adjust to their customers and can put themselves on a downhill path.