This article is part of the On Tech newsletter. You can sign up here to receive it on weekdays.

The last quarter of a century of computing was like an open, vibrant, and somewhat unruly nightclub. It was mostly good for all of us.

Let me explain why last week’s half-death of Android smartwatches resurrected my concerns that the velvet ropes are going off outside of this party and that new ideas may hang around the door. (Yes, I’m going to abuse that metaphor.)

I fear that the most important technologies of the future from technology giants will become more closed and controlled than the PCs, web browsers and smartphones that dominate our digital lives today.

This is how computing worked: Microsoft (and Apple) created the dominant brains of PCs, and Google and Apple did the same for smartphones. But these brain-makers admitted – sometimes reluctantly – that they could not be successful on their own.

She and we were better off because their technologies were gateways to playing games, scrolling Instagram, keeping tabs on corporate payrolls, and doing tons of other things that Microsoft, Google, and Apple couldn’t have done themselves. That’s why we have smartphone app stores, web browsers roaming the world, and PC software that Microsoft has nothing to do with.

These predominant forms of arithmetic are like nightclubs with lightly controlled velvet ropes. Everyone knows that the best party brings together a colorful and somewhat unpredictable group of people.

But now the bouncers are getting strict. Technologies that could be the next big thing – including goggles that overlay artificial reality in the real world, voice-activated digital assistants like Amazon Alexa, and self-driving cars – are mostly pulling people into the digital capabilities that device manufacturers create and lock down.

Many companies that develop self-driving cars develop everything from computer chips to steering wheels. Devices that connect our televisions to streaming video services are almost as tightly controlled by their developers as the cable television systems of yesteryear. Outside companies make apps for Apple Watch devices and voice-activated echo speakers. Most of the time, however, we use these devices to stay in a world created by Apple or Amazon. If this is a party, it’s one with the dominant host dictating almost everything.

These relatively closed systems can be temporary. And complicated technologies can be better, safer, and easier to use when developers control everything over them. However, I worry that we may miss out on new ideas as these nightclubs get tougher in the digital world.

To see what I’m worried about, let’s take a look at Android for Smartphones and Smartwatches. (I won’t blame you if you didn’t know there were Android watches.)

As with its Android smartphones, Google has used open technology for watches so that almost everyone can tinker with and redesign them. But the open party approach didn’t work at all. Google essentially admitted this a few days ago by combining its smart watch system with that of Samsung.

I can’t diagnose why Android smartwatches have failed. Smartphones may simply have been a golden opportunity for a technology like Android that cannot be replicated. Whatever the cause, I’m afraid it is the beginning of the end for open ramps to technology.

I could be wrong if I predicted more velvet ropes in our technical future. I hope i am. Because a lesson from recent history is that messy parties are great for all of us.

  • A public health experiment that is not a hit: Apple and Google have worked together on smartphone technology to let people know how close they are to others who later tested positive for the coronavirus. My colleague Natasha Singer is investigating why the exposure warning system has largely failed and what this says about the boundaries of technology giants to set global standards for public health.

  • Digital Comics and TikTok Videos That Are Not Careless: Social media developers help educate women and people of color about the symptoms of attention deficit hyperactivity disorder (ADHD), writes Nicole Clark for the New York Times. Please do not rely on TikTok videos for medical advice, but rather on the authors who create Nicole profiles who create accurate and traceable material on a disorder most commonly diagnosed in white boys.

  • The Video call should probably just be a phone call:: YES THANK YOU. Frequent video calls fry our brains. And you can instead make high-quality audio calls via audio apps like Zoom, FaceTime, WhatsApp or Google Meet, writes the Wall Street Journal. (Subscription required.)

Here’s a public library guard doing a safety temperature test on a kid’s kite and his nutcracker named Nutty. (Many thanks to my colleague Erin McCann for tweeting it.)

We want to hear from you. Tell us what you think of this newsletter and what else you would like us to explore. You can reach us at ontech@nytimes.com.

If you do not have this newsletter in your inbox yet, please register here. You can also read previous On Tech columns.