So i think it cannot replace by another crypto because bitcoin is the only one that imitate of other cryptocurrency.
Don't be so sure about it. Bitcoin is facing a lot of competition from Bitcoin Cash, due to the scaling issues. A few days back, the exchange rate of BCH even reached as high as 0.4 BTC. A lot of the experts were claiming that BCH was going to overtake BTC in terms of market cap. But BTC somehow managed to survive, thanks to the reduction in the number of unconfirmed transactions.