What a restaurant owner says “the food will speak for itself” or “we rely on word-of-mouth,” it’s their death sentence. On top of having good operations (pricing, staffing, quality, etc.), you have to do marketing. I know from my experience in restaurant consulting that a very, very small percentage of restaurants can survive on word-of-mouth alone.
Have you ever noticed that the most trendy or successful restaurants in any city still do a ton of marketing and advertising? And that the least successful restaurants continue to do nothing?