Many do. There is a range of products. When I was in Kiev, asking locals, which brands to select, they pointed out 1 or 2, and Coca/Pepsi-made were not among them. That was the recommendations from the older/middle-aged generation, who remember the taste of real Kvas. However, the placement of the products favours Coka/Pepsi, and the younger generation recommended them - acquired taste. This despite that Coca/Pepsi-made Kvas has as much in common with real Kvas as Fanta has with freshly-pressed orange juice.