Most airport bars are geared towards frequent flyers who aren’t there to relax or experiment with drinks. In the mornings most frequent flyers go for bloody Mary’s and screwdrivers. Late afternoons most are whiskey, scotch, rum, or gin and tonics. Evenings are usually beer and wines.
Those are old faithful drinks for frequent flyers and easily fall into the 20/80 retail rule. 20 percent of the drinks available account for 80 percent of sales.
Airlines and airports know this so they aren’t going to pay for high priced bartenders when all they have to do to stay adequate for airports are just being able to make the above drinks.
Pareto’s Law at work, even here..