Bitcoin will eventually be supplanted by another cryptocurrency that does not utilize a public ledger.
When well informed about and given two cryptocurrencies to choose from, each equal in all respects but one being public and the other private, people will choose the latter for being closer to cash metals etc levels of privacy. It is woefully unfortunate that the first cryptocurrency Bitcoin-BTC did not offer much therein thus setting and tricking the entire space into abysmally low thought expectations for a decade. Privacy, non-history UTXO state db's, much higher tx rates, low fees, distributed, minimal features, no premine, founders, tax, stakes, or governance... and cross chain DEX (CCDEX)... as before, all likely to be among a list of elements needed for a crypto"currency" to survive long term. BTC and other legacy coins lacking therein, will face very significant competitive pressures in the marketplace, not least of which in race to contend as a digital analogue to physical cash, metals, cows, etc... money, currency. Overall, BTC has already fallen to 65% mktcap and 1/850 active currencies. Lame metrics but conveys point.
snowden also said that the NSA can't break tor.
Such blanket context is unlikely.