bitcoin is popular but its possible that any other cryptocurrency replaces bitcoin it can be by yhe price or by other factors. no matter what it is but we know bitcoin is going ro gather a lot more popularity when all the 21bitcoins will be mined
Do you really think that another crypto currency will come and survive for so many years like bitcoin and gain a price and popularity like bitcoin and then it will replace bitcoin? That does not seem to be happening, bitcoin has almost everything a person might want from a crypto currency so i don't see any reason bitcoin getting replaced.
That happens all the time especially in the world of technology, look at apple they created a beautiful PC but then IMB created a dirt cheap PC and outsold apple, it was only when apple created new and incredible products they reached the top again, it is just the nature of the tech business.