It's really baked into the experience, and there's over a century (maybe two?) of evolution of cocktails that play well with it. I think the harsh flavor helps

It's really baked into the experience, and there's over a century (maybe two?) of evolution of cocktails that play well with it. I think the harsh flavor helps balance a lot of strong flavors and lets you build up powerful and complex combinations without anything becoming overwhelming. For now, mocktails are still just mock cocktails. They are missing the backbone that alcohol provides. Someday another strong flavor backbone will be discovered, and a new family of drinks will be built around it, with an new name. They'll be too good to call "mocktails."