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.
I dont think so. Because bitcoin the most trusted currency as of now. So i dont think that there's anothed cryptocurrencies can beat bitcoin. Because bitcoin is known and becoming more famous as the time goes by.
A few months back, Bitcoin's share in the total crypto market capitalization was above 90%. This figure has come down to around 45% now. So you can't be certain that no other crypto can beat Bitcoin. There is a chance, albeit a small one.