Zionism kind of just looks like one of the branches of evangelical Christianity. As far as I can tell their beliefs and practices wouldn't be out of place in parts of the US. Things like the robes and faith healing have passed in and out of popularity for a long time, like in some of the weirder Pentecostal Holiness. Since the term Zionism doesn't seem to be anymore specific than the term Evangelical it's kind of hard to determine what the spread could be. I suspect maybe a stronger spread in Africa is really the only place it could go. Maybe a Great Awakening style revival takes place?