Yes, sometimes an open house does benefit the listing agent, or the agent that holds it open as far as generating leads. But I personally have had 2 homes go under contract from an open house in the last year! (unfortunately, I was not the one at the open house, another agent did it for me). If you get people in your home and increase awareness is that not your optimum goal. Get it to as many people as possible. The folks that come to the open house may not be the buyers.....but they may tell someone at work or a family member about a great house they went through and refer that person to your listing. Don't rule out the open house. It can be indirect marketing!
If you have not had any showings in 30 days, I would ask your agent to bring you updated comps! You may want to investigate where you are priced compared to the rest of the market. Have you done a just listed mail out to surrounding areas to make sure everyone know there is a house for sale in their neighborhood? They may know someone wanting to move into the area!
I appreciate that it is frustrating trying to sell in a stale market! Work with your agent when possible. It will be more profitable for both of you.