In the very beginning, it was restricted to a very, very small list of users in the military and colleges. At the time it seemed like a very useful tool and pretty fun to play with. The next phase was Mosaic and then Netscape creating the web, which also felt like a pretty neat and potentially useful toy. I remember passing around sheets of paper with URLs to type in, before there were search engines. And then it all exploded, everyone had to have it, and things changed a lot as the average user was both way less technical and way less well-behaved.
Given that, blockchain may be in a similar state to the early-middle Internet. It's out there, you can play with it, it's neat and seems useful even if for most people that practical purpose is elusive. Maybe someone has yet to create the Netscape that turns it into a must-have tech, but it might be happening as we speak.
(Edit: TCP/IP came out in 1983, and HTTP in 1990. In 1995, the year of the Netscape IPO and when everyone "knew" the web was a big deal, there were 40 million Internet users. Now there are about 32 million Bitcoin wallets. I think some of the other answers are remembering things a bit later in time, or more colored by hindsight.)
On the other hand, quantum is much farther out. The percentage of people who have used a quantum computer at all is minuscule. When it does become useful, it may be too expensive to see mass adoption for decades.
> I remember passing around sheets of paper with URLs to type in, before there were search engines
Wow, what a throwback in time! I had completely forgotten that. Thanks for the sweet memories!
Also, I agree with your take. One key difference re. cryptocurrencies might be legal context however. Internet wasn't stepping on governments toes, more like disruption of the telco sector (which was already focused on emerging mobile at the time, a decade prior to smartphones). I'm not so sure the road is wide open for alternative currencies, because central banks and, oh, stability of the economy etc. It's a much tougher sell.
Blockchain itself however, the tech, may have killer-apps and uses — either as an evolution of currencies, or decoupled entirely from 'currency' (trustless secured distributed databases may fit many needs IMHO, notably for social purposes like contracts or unhackable communication).
Given that, blockchain may be in a similar state to the early-middle Internet. It's out there, you can play with it, it's neat and seems useful even if for most people that practical purpose is elusive. Maybe someone has yet to create the Netscape that turns it into a must-have tech, but it might be happening as we speak.
(Edit: TCP/IP came out in 1983, and HTTP in 1990. In 1995, the year of the Netscape IPO and when everyone "knew" the web was a big deal, there were 40 million Internet users. Now there are about 32 million Bitcoin wallets. I think some of the other answers are remembering things a bit later in time, or more colored by hindsight.)
On the other hand, quantum is much farther out. The percentage of people who have used a quantum computer at all is minuscule. When it does become useful, it may be too expensive to see mass adoption for decades.