Maybe. It would be a matter of choice, if people decide to use more ZEC with its privacy features, or stay with Bitcoin. The pioneer cryptocurrency may gain better traction if it manages to adopt ZEC's privacy technology, but I believe that ZEC will remain in crypto land since it was the original cryptocurrency which brought this idea.

ZEC may be good in its technology and all, but it lacks cross-platform compatibility, and user friendliness which are the keys to any cryptocurrency's success. The dev team for ZEC is real slow, lacking to bring real innovation into the cryptocurrency other than its privacy feature itself. So the only thing that ZCash has which is unique is its privacy feature. Other than that, it is just a Bitcoin clone. Just sharing my thoughts