bitcoin would be never replace by another crypto currency because bitcoin getting too much power and bitcoin adopting is very much high and we know that bitcoin increase its price too much faster than other currency.
It is well known the potential of Bitcoin, but no matter how popular it is, it will not stop other technologies from appearing. But since Bitcoin continues with a good team of developers, there is no reason to worry, because in most cases the altcoins have improvements that can be implemented in Bitcoin. The problem is that it is not very easy to reach consensus on the network for this to happen.