Oh for sure but with how much of a stomp One Piece vs Dragon ball is in Japan, I'm not sure there is that much of a difference.
Worldwide appeal might still hold Dragon ball at the top right now tho.
It's weird. The One Piece manga sells much better than the DB manga (in Japan), but when you look at overall merchandising and games Dragonball dominates One Piece even in Japan. See Bandai's numbers for example.
Even without a show on air, Dragonball merchandising makes more than double of what OP makes in Japan (Sales of IPs (Toys and Hobby Business, Japan)). And outside of One Piece's peak popularity around 2010, even the game push has generally been smaller than what DB gets. The manga was (and still is) extremely successful, but for some reason they were unable to really push success elsewhere outside of that peak era.