To believe (e.g. to be certain) something like that does not make rational sense. To say that is a statistic probability makes much more sense. However, this has been discussed over and over again. In order for the cryptocurrency space to thrive, it would be most suitable if there were multiple coins at the top and not just one (as currently Bitcoin is). Nobody can say that either one will happen for sure; they would only be speculating.
Bitcoin for now is upgrading and its value increases dramatically so thinking that bitcoin would be replaced by other crypto-currencys thats imposibble for know. We all know that bitcoins value is depending to the support of people so many people continue to choose bitcoin than any other crypto-currency. That is the fact and when bitcoin becomes more popular many buisness will be open on accepting bitcoin so it may be the future ot bitcoin. It cant be replaced by any other. Because bitcoin is just starting to grow more.Also because we are addicted of using bitcoin and use it rather than using any other currency we are unknown of.
This is the main factor bitcoin will not be replaced !
same thing was told about e-gold about 10 years ago and e-gold is the past now.
Bitcoin will be the past in the next 2-3 years when another e-currency will arise
Right we can expect that happens in near future when we will see some other currency taking over bitcoins which will be holding better features then bitcoin and it will take no time for people to switch to that currency keeping bitcoin behind.