News flash: it already popped. 70‰ from top. ICOs dried up.
Blockchain market cap is about $300 billion now. Should the next major tech wave be worth half a Facebook? IMO, yes, and more.
Blockchain has already proven 2 major use cases (e-gold and ICOs) and several minor ones (unstoppable casinos, prediction markets). Doubters are in for a bunch of regret.