If I can manage without a cigarette from enetring the terminal in one country to exiting at another I'm damn sure people can manage without alcohol.
Have you considered the possibility that the reason Singapore Air spends US$8 million per year on champagne and fine wine for its premium passengers, is because some passengers rather enjoy alcohol ? Orange juice made from concentrate just doesn't have the same aura as Dom Perignon !
Singapore Airlines Singapore Air keeps champagne budget to win first-class fliers - eTurboNews.com