You know, back in 2015? Ah, we were so young and naive then. And the music was horrible, to boot.

How were we to know all this talk of autonomous cars coming to market by 2020 and taking over by 2035 wasn’t just tech-bubble bullshit from hare-brained billionaire investors? There had been literally zero precedent for such a leap in consumer adoption of a new and imperfect technology.

I mean sure, we could have looked at the growth of the original U.S. car market, which in 1900 stood at all of 5,000 cars, then grew 50x within a decade, 10x in the next, and by that time had nearly saturated the new car market to the point that one of the largest manufacturers decided to buy up and destroy 650,000 used cars just to ensure there would be enough buyers for the new ones. We could’ve done that.

Then you’ve got commercial air travel, which by all accounts should have been one of society’s greatest fears and most difficult sells. Welp, it turns out that despite having to develop its infrastructure over the course of The Great Depression and WWII, commercial flight adoption ballooned over its first 10-year period, and continued on in the following decade. Strangely, people didn’t seem to mind that passenger flights in those days were uncomfortable, slow, and sometimes half of an average American’s annual take-home pay.

I suppose one could offer up the personal computer market as evidence too. 1978 was the first year you could actually buy a computer you didn’t have to put together yourself, and one that could actually run software. Sure seemed like that technology had a long way to go, but businesses capitalized on the software angle so quickly that the presence of a PC on someone’s office desk became a status symbol within a decade, and a near-requirement just one decade later.

The New York City subway probably would have been relevant to study as well, since, like autonomous cars, it tells the story of how people might take to an innovation developed atop an already-existing commercial platform (in this case, the above-ground rails which already ran through parts of the city.) To that end, it probably would’ve been smart to notice that NYC’s subway system hit critical mass on the very first day it opened, and in the decades to follow grew to its all-time high in ridership. That is to say, the subway reached service volumes in its first quarter-century of operation that have yet to be matched in the 85+ years since.

The poorly-dressed nerds of 2015 also might have considered the growth of the worldwide web, since it’s one of the few examples mankind has of something that has grown through the contributions of computer programs, and not just human efforts.

Consumers couldn’t really access the web until the “WWW” iteration of the Internet and dial-up service were introduced in 1989. And since no one knew how to write code, and there was pretty much nothing on the Internet to see anyway, it would make sense for such technology build its presence slowly over the first few decades. Except that didn’t happen. It grew at a rate that is almost impossible to visualize on a chart, and within 20 years it had cemented itself as the greatest invention since fire. Probably just dumb luck, I’d wager.

Now, the mobile phone market probably wouldn’t be an example to come to mind, what with all those years of weird flip phones before the iPhone came in and swept us off our feet, and the stone-aged “car phone” which marked you as a successful business human prior to the handheld phone’s introduction in 1984. I mean, a house phone, a car phone, and a hand phone? How fast can that take off?

Well, pretty fast. Even before the iPhone, mobile had made its mark, with 100x growth in the first ten years of its existence, and the kind of volume twenty years later that resulted in the UK having more mobile phones than people. Again, that happened while the iPhone was still a twinkle in Steve Jobs’ eye.

Oh, and we could have remembered television too. The ol’ boob tube, a significant investment for any American in the early days, with the reward of a few dozen channels and hours when there was literally nothing on. Yeah, that didn’t stop Americans from embracing TV at a staggering rate.

So, perhaps there were some indicators. But besides cars, air travel, the Internet, cell phones, the subway system, computers, and television, how else were we to know the autonomous car market would ramp up so quickly?

Alright. Besides radio, VCRs, DVD players, broadband, cars, air travel, the Internet, cell phones, the subway system, computers, and television. And iPhones. And Facebook.

Sure, the benefit of hindsight lets us toss around a bunch of fancy stats that could have possibly predicted the growth of autonomous vehicles… but everyone’s a genius in hindsight, aren’t they buddy.

Trust me: in 2015, it was anybody’s guess.