Coronado is going to remain a destination neighborhood until it and the rest of San Diego falls into the ocean.
The main reason to watch it as a market is to demonstrate how widespread and systemic the trend for decline is. Declines in Coronado prove that it isn’t just the beater neighborhoods that are subject to losses while the rich neighborhoods escape unscathed. It proves that even wealthy people from out of town won’t pay more for a property than what their options are and emotion isn’t the only factor involved.