Corner pharmacies, once widespread in large cities and rural hamlets alike, are disappearing from many areas of the country, leaving an estimated 41 million Americans in what are known as drugstore deserts, without easy access to pharmacies. An analysis by GoodRx, an online drug price comparison tool, found that 12 percent of Americans have to drive more than 15 minutes to reach the closest pharmacy or don’t have enough pharmacies nearby to meet demand. That includes majorities of people in more than 40 percent of counties.