If you take into account how much money was spent on its extraction, then the price equal to zero will never be. Perhaps ether will replace bitcoin, but bitcoin will probably cost as antiques.
Thats not going to happen in any way or under any circumstances. We all are familiar with this fact that bitcoin is the strongest and oldest player of the market and it has never stood second to any coin. Rather all other coins in any form are following it for their market trends. Ethereum could be best among its community but this is mere exaggeration that one day bitcoin will be surpassed by it.