It will never happen again because the way to promoting new project has changed. In the past because the cryptocurrency community is not big so it was a good way for XEM to reach more people. Now everythign has changed, more better ways to promote a project.
You should never say never cause we are living in a changing world where unimaginable things happen and in the cryptocurrency market any thing can happened that is why it call a volatile society where no one can never state what will happen in the future and at that we will always keep hoping for a better future so if you believe in any project I think the best thing to do is to hodle and hope for the miracle.