I don't think that bitcoin will be ever replaced by any other crypto currency as I don't see any competition to bitcoin at a moment and even in future bitcoin will keep on updating itself with the demand of people so its hard for any crypto to replace bitcoins.
There is no competition for bitcoin at a moment but it can be changed in future when new technology will arrive and at that time there is a possibility that bitcoin can get replaced by other currency.
i think bitcoin is the most popular currency as majority of people are using it and as you think that in future it could be replace by new currency with the arrive of new technologies, well so i think that when in future the new technologies arrive so bitcoin will also adopt these technologies and update its self.
Yes that is a good point to be noted if any new thing can adopt a latest technology for its strength then why bitcoin will not adopt it if they feel it as necessary. They will definitely adopt that technology and will prove itself as more stronger than any other coin.