When I saw this news release on Thursday, I had the thought that perhaps the reason they have hired a new Executive Chef (again) was that the previous one(s) was getting frustrated with poor service (food cooked but not presented timely.) and decided to move on to a place that can better utilize his talents.
We watch a lot of Top Chef type programs, and Gordon Ramsey, and often they have a simulated restaurant "challenge". Occasionally, service falls down and hurts one sides chances of winning the challenge. These contestants are all very good chefs in their own right, and putting egos aside, if they get upset about poor service, it would not be a stretch to think perhaps these past chefs may have left due to poor service perhaps affecting their reputation.