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.
That only means that other useful projects have appeared that is all, it was impossible for bitcoin to maintain that percentage and even if that percentage has been cut in half, the market cap of bitcoin since those times is 7 times higher which is not bad at all taking into account that it took less than a year for that impressive growth to happen.