Now Silicon Valley is in the middle of an artificial intelligence boomthat bears some obvious resemblances to the dot-com boom. Much of the rhetoric about a glorious world to come is the same.

For all the similarities, however, there are many differences that could lead to a distinctly different outcome. The main one is that A.I. is being financed and controlled by multitrillion-dollar companies like Microsoft, Google and Meta that are in no danger of going kaput, unlike the dot-com start-ups that were little more than an idea and a bunch of engineers.

Amazon is not selling less toothpaste as it shells out billions on A.I. data centers, and Google is not selling fewer ads as it develops foundational A.I. models.

The internet was a new platform in the 1990s. It took time for people to accept the idea of being online, and for technology like broadband to be put in place that allowed them to thrive there. Many business leaders, by contrast, are eager to take up A.I. as soon as they can.

“We get bubbles when everybody believes the price cannot go down,” the venture capitalist Ben Horowitz wrote in an email. “The clearest sign that we are not actually in a bubble is the fact that everyone is talking about a bubble.”

The three most highly valued companies of the dot-com era were Cisco, Microsoft and Intel, all of which supplied the technology that made internet start-ups possible. Each was valued around $500 billion at its peak.

Today, Nvidia, the chip maker that plays a similar role for the A.I. boom, is valued at more than $4.5 trillion. It and other A.I. companies such as Amazon, Google, Meta and the privately held OpenAI are together worth more than the $17 trillion capitalization of the entire stock market in 2000.

The wealth and power of these A.I. companies are partly why Jerome H. Powell, the chair of the Federal Reserve, sees no cause for worry. These companies “actually have business models and profits and that kind of thing,” he said in October. “So it’s really a different thing” from the dot-com bubble.

To a large extent, the dot-com boom was a revolution from below. People around the country packed their bags and headed to San Francisco in the hopes of striking it big, just as they did in the original gold rush 150 years before. More than 2,200 dot-com companies went public between 1996 and 2001. At the time, it seemed like a lot.

By contrast, A.I. is a less populist phenomenon. OpenAI, Google, Meta and Microsoft have been engaged in a well-documented bidding war for talent, but those without expertise have little chance. There are 972,000 companies with .ai internet addresses, although it is unclear how many are viable enterprises.

“In 1996, Netscape had 90 percent of the browser share, and we only had 50 million users, so there were 55 million people total in the internet market and roughly half of those were on dial-up,” Mr. Horowitz said. “At the same time, the software to build internet services was super immature and expensive, as was the corresponding hardware and the bandwidth.”

A.I. is very different, Mr. Horowitz contended. The internet is a network, and its value increases as more people are added, he said. Online retailers in 1996 could reach only a small fraction of the population. Amazon now reaches just about everyone.

A.I., on the other hand, is a computer, Mr. Horowitz said. “Computers can be valuable immediately. A.I. is certainly valuable immediately,” he added. “A.I. products are working so well that we are seeing revenue growth that dwarfs anything that came before it.”

A little-acknowledged worry with the A.I. boom is that impulses toward fraud will find fertile soil. That means the more unsavory aspects of the dot-com era may be the likeliest elements to make a comeback.