The problem is that other than speculation there is almost zero adoption, and it isn't coming any time soon.
And it terms of speculation people have a belief (whether correct or not, but largely correct) that "getting in early" is relative to other speculators. And of course you can't be ahead of other speculators if most of the coins are already owned by other speculators.
Also the timeframe of interest for most speculators is not 10-20 years, which is looking like something more realistic for end-user adoption. The only real attempt at crypto adoption we've seen so far was the retail acceptance that started last year (Overstock.com, etc.) and that has almost entirely flamed out (most of these retailers report usage down 80% or more, not growing).
I also have the perception that darknet use is way down from what it was. I base this not on anything from the crypto space at all, but from how many people from outside the traditional cryptospace I encounter who are buying drugs online. Many fewer are doing it now.
If no killer app and actual use emerges, then I agree that the speculative manias are finished.
But all the use-cases (remittances, black market trade, micropayments, etc.) at least one should become an easy-to-use, viral thing at some point. If it's like e-mail and takes 20-30 years from invention to viral spread among the general population then we (speculators) have all shown up to the party way too early.
But e-mail required cheap computers, cheap modems, cheap internet access, etc. before it could really start spreading virally. There were a bunch of blockages. So IMO, bitcoin will not need 20 years to get a viral use-case going (if it ever will). Something polished and nice should come out closer to 10 years after invention. Perhaps 2019.