The answer I came up with was not much, after all if I am paying a business or First fare then I get my lounge access, massages, chauffeur service and improved food whichever airline I go with. So why don't I just show them no loyalty at all and just pick whichever one has the best route or price at the time.
Welcome to the converted. Its most refreshing to realise that having no loyalty to anyone at all actually means you pick the right airline for the right route at the right time and more often than not get pleasantly surprised at the result.