At least one of the reasons...
I heard last week that a wonderful little restaurant in Tulsa is closing, The Brasserie. I'm sorry that this is happening, but I'm not surprised. The Brasserie was only open for dinner.
This is problem.
As a business owner, I face several situations where I must invite people to lunch and dinner. Being an extremely busy person I LOVE having a "go to" place, where they have a great menu, great pour, and they KNOW who I am, and what I like.
Restaurants that aren't open for lunch can't be my "go to." Even if they are wonderful at dinner, once I have established a relationship with a restaurant I tend to be a loyal customer.
I would wager that people like me spend more money at restaurants than the average person.
I think Mahogany isn't open at lunch. I have only been there once, several years ago.
I rest my case.