I don’t know any popular drink with grape flavor in Israel. The only one I can think of is popular because it costs so little. As a kid when you happened to have only one ILS, and you were out on a very got day, there was nothing like a grape-flavoured “Tropit” to satiate your thirst. They also give them around in summer camps for the same reason (that’s only my perspective though. I acknowladge people’s right to like grape flavor in all types and forms)
Also kids are crazy about the grape juice in the kidush. That counts for something doesn’t it?