Not possible I think Bitcoin will always be the main currency. ETH was doing good breaking past 400 so quickly but, as soon as BTC got dumped (about $1000) ETH too fell sharply with bitcoin.
Of course, Bitcoin will still have to keep its leading position. But sooner or later, it will be replaced by a new technological coin that will topple Bitcoin from the pedestal. Perhaps it will be Ethereum, or perhaps a completely new coin.