I don't know anything beyond what the N&O reported, which implies that Ben & Karen Barker are ready to spend more time with family. Its a shame, as not only is Magnolia Grill a great restaurant, it has been the training ground for quite a few other area restaurants started by chefs that left the Magnolia Grill nest.
The list includes: Nana's, Elaine's, 18 Seaboard, Vin Rouge, Watt's Grocery, Four Square and I am sure there are plenty I missed.
I'm sad to see it close and may try to get there one last time in the next couple weeks.
I'm glad that they had the influence they did on Triangle cuisine, as the area might be a culinary wasteland without them.