Yes there is a chance that this will happen but we will see what is gonna happen lets hope on a good future and lets say that the bitcoin will not get replaced.
I think its already too big to get destroyed by another altcoin honestly.
No there isn't a chance. If some cases that bitcoin will be destroyed, all alts will follow the same fate.
Without bitcoin other alts are nothing. Alts role in the crypto world is just to take profits, that is the only reason why there are always new alts.