I would think that central banks won't collapse for so long until they are not an integral part or the main pillar of the elites' wealth anymore. In other words, the elites would need to shift their wealth into assets that are not affected by central bank collapses. I don't claim that I fully understand the financial system with all its different angles, but my assumption is that the whole banking sector is so deeply entangled with central banks that a collapse of central banks would mean a collapse of the entire financial sector, which mean a collapse of the entire system built on the financial sector, i.e. the world economy.

BTC is now a system outside the existing system. That makes it so interesting to own. Of course a collapse in the global economy would affect BTC because people would suffer from poverty and all the bad things that come with financial distress or let alone collapse. The urge to sell BTC to cover expenditures would certainly create selling pressure for BTC, too. Yet it could be the currency or wealth preservation tool that people agree upon globally. But it would be interesting to do some research as to how a spill over effect of a collapsing central bank system / economy could affect BTC after all.