Here’s the thing about restaurateurs: They don’t really care about who has the best ramen in the East Village. They’re not really that interested in where Paul Liebrandt’s restaurant will be, and they find avant-garde desserts about as compelling as algebra. But when Steve Hanson opens a restaurant? That, that is something they’re interested in. The fine art of making money via replicable concept restaurants is one at which Hanson is an acknowledged master, and that helps to explain why the main room at Primehouse last Thursday looked like a who’s who of big-time restaurateurs.