There has been no killer gadget at this year’s International CES technology show. Instead, something more subtle has emerged as the keystone of the tech world.

I'm talking about the smart, central voice assistant. Yes, even that may sound a bit old hat for those who’ve been paying attention. Techies have been talking about connected gadgets and the potential centralizing power of artificial intelligence for years now. The difference is that at this year's show we're seeing so many high-quality gadgets that actually live up to that promise. We’re out of the prototype stage and onto the practical. Rather than having to do a lot of research about what will work with your particular voice assistant, you'll be spoiled for choice.

In fact, you almost can't turn a corner -- and there are many of them at the 2.47 million-square-foot show — without seeing a product that features Alexa. Amazon's voice assistant jumped to an early lead in the market at the show. Whether Alexa can keep that lead, however, is debatable. (Amazon chief executive Jeffrey P. Bezos also owns The Washington Post.)

Virtual assistants can now understand what you say and even interpret the many ways you may say it. Shawn DuBravac, an economist for the Consumer Technology Association, said that machines now have the same word error rate — that is, the batting average of understanding what we've actually said — as humans. That's up from a 23 percent error rate in 2013, meaning that the tech is getting better, and quickly.

That fact has made the dreams of a "Star Trek"-like computer come closer to reality. The hope is that these assistants will move even beyond our sci-fi dreams and learn our habits and needs well enough to anticipate them. At the show, voice assistants were being shown off in cars, refrigerators, nightstand clocks -- they were just in everything. 

From a privacy standpoint, all that data collection can be off-putting, meriting more discussion than a week-long electronics show can accommodate. But from a convenience standpoint? It's stunning to think about.

In the next few years, the competition to make the best voice assistant will reach new heights, as tech companies jockey to be the voice of your connected life. But the battle is halfway won for voice-control evangelists. A sizable number of tech companies are already fully on board with voice-controlled gadgets and system. Touchscreens and buttons won’t disappear completely, at least for now, but the most basic functions — turning lights on and off, turning thermostats up and down, pausing and playing — are solidly in the voice-control realm.

It’s not perfect yet -- it could take a couple of years to fix the annoying “No, Alexa, I said TURN OFF THE LIGHTS!” issues that can turn people off of smart assistants. Even on the floor at the showcase CES, few voice technology demos worked smoothly (followed by quick assurances from the demonstrators that they worked perfectly well in the quiet of the morning set-up).

So, consumers will still have to live through the bugs and growing pains of voice assistants over the next few years. Machines are now learning from us, which in some ways resets the cadence of innovation itself. Technological improvement is now about constant, small steps rather than giant leaps. It's less about adding to your life, and more about steadily subtracting hassle from it. That means we may not have a moment that feels like the future has arrived; we'll just slide into it instead.

But a quiet revolution is still a revolution. And the evidence that these gadgets can actually live up to their promised potential — and maybe even beyond what we've forseen — is strong. This year more than ever, it feels like we've crossed the Rubicon. Soon, there won't be the need for distinguishing between a "smart" version of a gadget and a dumb one at all.