The biggest area of focus for companies with carbonated soft drinks today is perhaps flavor innovation.

To sustain the sales volume achieved by a new flavor, companies in subsequent years must develop another new flavor, but it might fail because “a lot of consumers have short attention spans, so they’re off to the next big thing,” Hemphill said.

A recent offshoot in carbonated beverages is gut health/prebiotic sodas like Poppi and Olipop, he said.

“You could argue whether these are actually CSDs or if they fall into another category,” Hemphill said, noting they offer a health benefit but nonetheless are carbonated, flavored and sweetened.