Pretty much everything successful now was ridiculed or dismissed in the past, but that doesn't mean everything that was ridiculed or dismissed became successful.

And even those things that became successful did so in a form that the contemporaneous positive predictions did not expect. The 1990's predictions of the Internet was of decentralised power and freedom of information, what actually happened? There was a land-grab, and a new generation of billion-dollar corporations have become established. Where once there was Blockbuster, now there is Netflix...

My prediction is the same will happen with cryptocurrency and blockchain applications. The technology will live-on, mostly in non-currency applications (e.g. behind the scenes settlement rather than day-to-day transactions); most of the "land grab" phase will die off though. Then, one day, ten or twenty years from now, we'll realise that "fiat" currencies have been blockchain based since some un-trumpeted central bank upgrade eighteen-months prior. But no-one will have noticed, as they still spend "dollars" on a credit card... same as they always did.