The reason for Bitcoin’s design is precisely because a centralized/pegged alternative was tried and failed: https://en.m.wikipedia.org/wiki/Ecash Facebook’s currency is not a successor of Bitcoin, it’s an inferior reincarnation of a failed predecessor.
I personally think that Facebook's cryptocurrency will fail because today's climate is anything but trusting, but just because an idea failed in 1983 doesn't mean it'd fail today. There's also a strong possibility of it succeeding in the developing world and failing in the developed world.