it seems impossible in the present time but who know what exactly would happen in the future , there's always a chance to replace bitcoin but they can never make the same feature . it can never be replaced until the bitcoin mining and blockchain would go down .
Yes its impossible not only in the present time but in the upcoming years as well i dont see that happening.Because there is not even any comparison of bitcoin with any other altcoins in this crypto-world,bitcoin would always rule the crypto-world among all cryto-currencies.