This is a roulette game.
Until a crypto is chosen for ongoing trade - eg lets say Amazon backs bitcoin as its crypto of choice. This will level out the massive fluctuations because of underlying demand from the billions of dollars of turnover generated by Amazon annually, that will flow to bitcoin.
Further Amazon will be motivated to keep bitcoin values within a specified range for the good of its customers and its shareholders.
This is the only way a crypto can survive - at the moment cryptos' ( but not block chain technology) are just a cruel fade that will see many people burnt.
Further your point re Fiat currencies is not relevant - Countries control the value of their currencies with interest rates and have a vested interest in maintaining currency stability - no government could survive crypto style gyrations in their currency valuation.
I can invest $1 million to day in any AUD currency and be 100% certain that is 12 months time my max. downside would be say 15%.
With Crypto I could be wipeout.
Further the very high concentration of ownerships by the few in the crypto game, makes it rife for manipulation in a way currencies can never be manipulated.
ONLY Blockchain has business case not Crpyto's. And with the former it will be like VHS v Beta, Mac v Microsoft, Visical v Excel etc where a favoured blockchain will eventually dominate - many blockchains will therefore not survive.
