This is all pretty arbitrary. In the context of
pure engineering timelines, you don’t get to just pick arbitrary starting points.
The Internet took decades to reach “I can buy cat food from my home PC” because that’s how long it took the underlying computing and networking technologies to go from the first recognizable proto-technologies to the point where they enabled mass-market usage. If you start your clock in 1994 (or 2007) you can make that time look shorter, but it doesn’t change anything.
Similarly Uber was able to launch a GPS-based smartphone app only a few years after the first smartphone, because the technologies of 3G cellular, OS, portable computing, GUI, GPS, distributed systems etc. were all extremely mature by the time the smartphone launched. But if you measure from earlier points in the “portable computing” timeline you can make Uber look like a multi-decade pipe dream.
There’s no reason to believe that the technical barriers facing cryptocurrency (scaling, UI, key management) will follow dramatically slower or faster tech development curves than those previous technologies. There are still plenty of reasons to question whether there’s a “killer app” once the tech issues are sorted out, but they clearly aren’t yet.