I don't think that if bitcoin disappears then there will be other coins persists because during Bull and bear season the price of other coins are regulary fluctuates according to the ups and downs occurs in bitcoin price.
Bitcoin is a successful coin you must choose bitcoin but if you doubt that someday bitcoin will not be here to give us profit then you can choose gold because if bitcoin become disappear then all other coins will surely disappear too but gold is not related with bitcoin.
If bitcoin were to disappear, something incredibly difficult to happen due to the decentralized nature of bitcoin, then this means that a very serious problem was found on its code from which it is impossible to recover, so it is to be expected that under that scenario people will lose confidence on this market and all coins will crash all the way down to zero, so what to do for those which want to prepare against that scenario? Buying precious metals is a good option and any hard asset will most likely do a good job too protecting your capital.