Why do businesses in posh neighborhoods always close/new ones open?

In many rich neighborhoods, i noticed that many businesses are constantly closing and new businesses take their place very often. Every time I drive through these ritzy areas , there is always a restaurant that closed and a new one opened up ,,etc.. WHy is this? Is it lack of clientele? High rent?

Many businesses open in these areas to get the local people as clients. Unfortunately the people in these neighborhoods didn't get rich by not getting good value for their money. These people are excellent customers, but only if you provide either excellent value or an outstanding product or service. These people are all mobile and will go across town to buy what they want if the local businesses don't have what they want at a price they want. In a less posh area you might be able to survive will higher prices or lesser quality service as your customers are not as willing to leave the local area.