Your problem may be that you're using hindsight to see the PC, internet and mobile eras and using somewhat irrational exuberance to view the current "disruptions." It's a pretty good bet that not all of them will pan out or have the kind of pervasive impact on society that you're predicting and that 20 years from now, again with hindsight, you'll see the 1 landscape-altering technology that defined the current era and fits into your linear model.

For instance, people have been predicting that VR will be the next big thing for years now. I remember a birthday party more than 30 years ago at an arcade with an expensive VR setup that, while far more limited than today's applications, was still an awkward piece of headgear that's more of a novelty than a potentially-ubiquitous change to society. It's still possible that we hit some sort of inflection point where technology improves to the point where AR/VR becomes unobtrusive enough that it can become ubiquitous, but that's by no means a certainty.

Similarly, I think the jury is still out on IoT, drones, 3D printers and cryptocurrencies/blockchains. If I had to place a bet, I'd say that when we look back on this time period, we'll be talking about machine learning and AI defining this era. The rest of the "current hotness" technologies I could easily see not getting that big.