Here is where the story gets back to the rest of us: This family commands its princely system, which cost $400,000 to design and install, from something as simple as an iPad (or, in this case, any of the seven iPads conveniently located in various parts of the house). Before the advent of touch-screen phones and tablets, Stearns said, he would have used custom-made controllers for this automated system – and those devices cost several thousand dollars each. But the iPad controller costs $499, a big savings. And because the iPad can be customized with different apps, it can be made to control lots of companies’ systems.

In this way, as prices fall at the high end, they become more approachable for the rest of us. Consider a very basic security and home-automation service offered by a company called Vivint. The package carries a base price of $200, and a monthly service fee of about $70, including security monitoring.

To be sure, Vivint’s system lacks the refinements of a higher-priced custom system installed by a dealer affiliated with Pedigo’s association; Vivint’s system does not plug into a home-entertainment center, for example. But for many people, a simple system can be very helpful. Vivint’s includes a video surveillance camera, an automatic door lock, a remote-controlled smart thermostat and a module to control one appliance (extra modules cost a one-time fee of $39 each.)

“We think that the reason these technologies haven’t been adopted is because it’s been very complicated and expensive to have them,” said Alex Dunn, the company’s chief operating officer, “and we felt we could change that by changing the business model.”

Jake Zalewski, a San Franciscan who manages a network of college bookstores and travels frequently on business, said his Vivint system has freed him from worrying about all the little things everyone thinks about after leaving the house. Did he remember to lock the door, turn off the lights, set the air conditioner, turn on the alarm? He can quell all those concerns with Vivint’s app on his iPhone, from anywhere he has an Internet connection. “It just makes it so convenient,” Zalewski said. He is planning to install a second system at his house in Lake Tahoe, and is particularly looking forward to one feature in particular: turning on his hot tub when he leaves San Francisco, so it's ready to be jumped into when he arrives at his home a few hours later.

Recently, Sigma Designs, a company that makes a home-automation technology linking many gadgets, announced that it had made its systems compatible with “smart meters” that utilities countrywide are rolling out to customers. This development may enable you to program your appliances to turn on and off according to the price of electricity.

Such advances are likely to be installed in the fanciest homes first. But as prices fall, it might not be too long before, finally, we are all in control of every corner of our caves.