I think it depends where one is. I grew up in the Bay Area and our vegetarian family's go-to place for special events was Greens at Ft. Mason. Prix-fixe and enjoy. Tried to find an equivalent in the Los Angeles area and was told by food/wine pros to go into higher-end omnivore places and ask the chef to make something appropriate. I was told that chefs here liked such challenges.

Failed utterly. Paid high prices for meh pastas and the "grilled vegetable plate." Learned my painful lesson and told the food/wine pros I knew that they were full of it. Didn't hurt that one of them came with me one evening to a place he recommended and saw what came out of the kitchen!