A middle-class man making 40,000 might not be able to buy a new BMW. But he can buy the occasional bottle of vodka for 35 a bottle. People are drinking less than they once did, but they are drinking better.
The big difference between beer and spirits is that spirits like vodka and Scotch offer consumers a wide range of flavors and mixable options and you can buy them in a range of price points.
Spirits are perceived as affordable luxury. People are more careful with their spending today. Maybe they can't buy a 40,000 BMW but they're willing to buy a good 60 to 70 bottle of Scotch. You don't get that kind of trading-up feeling with beer.