MaSSSoftech

IF Thomas M. Siebel can accurately see the future, computer science students with the entrepreneurial gene may want to look for a different major. And investors who think that information technology is a sector that will produce outsized returns should wake up.

In Mr. Siebel’s view, I.T. is a mature industry that will grow no faster than the larger economy. He contends that its glory days are past — long past, having ended in 2000.

I believe that Mr. Siebel may well be wrong. But his own illustrious career in I.T. makes his opinions a matter of uncommon interest.

Earning both a master’s degree in computer science and an M.B.A. at the University of Illinois at Urbana-Champaign, he was an executive at Oracle from 1984 to 1990. In 1993, he founded Siebel Systems, which sells software for tracking customers and sales prospects; the company was acquired in 2006 by Oracle, which paid almost $6 billion. In Mr. Siebel’s self-deprecating narrative, he was simply standing in the right place at the right time.

Addressing Stanford students in February as a guest of the engineering school, Mr. Siebel called attention to 20 sweet years, from 1980 to 2000, when, he said, worldwide I.T. spending grew at a compounded annual growth rate of 17 percent. “All you had to do was show up and not goof it up,” he said. “All ships were rising.”

Since 2000, however, that rate has averaged only 3 percent, he said. His explanation for the sharp decline is that “the promise of the post-industrial society has been realized.”

No new technological advances, he believes, would impel I.T. customers to replace the computer technology they already had: “I would suggest to you that most of what’s going on today is not very exciting.”

In his view, far larger opportunities are to be found in businesses that address needs in food, water, health care and energy. Though Silicon Valley was “where the action was” when he finished graduate school, he says, “if I were graduating today, I would get on a boat and I would get off in Shanghai.”

When I called him last month to discuss his provocative arguments, he was disarmingly modest. “I’m just an old has-been, I don’t present myself as an expert in this or any other area,” he said.

The huge difference in growth rates, pre- and post-2000, may seem so stark as to leave no room for an alternative view of I.T.’s prospects.

But the recent drop is not as steep as it seems at first. I asked Shane Greenstein, an economist at Northwestern University’s Kellogg School of Management who has written extensively about the computer industry, to take a look at the raw data upon which those numbers were supposedly based: the annual I.T. spending estimates published by IDC.

Mr. Greenstein’s calculations produced a more moderate compounded annual growth rate of 11.6 percent for 1980 to 2000, instead of 17 percent. (Mr. Siebel’s personal assistant said last week that the 17 percent in the Stanford talk came from a staff member who calculated from a reading of a chart, not from precise figures.)

When Mr. Greenstein looked at the full IDC data set, which goes back to 1961, and used other breakpoints to compare growth in earlier and later periods, he found that the most golden years of I.T. were in the 1960s, when use of mainframe computers spread widely. From 1961 to 1971, the compounded annual growth rate was 35.7 percent, more than three times the rate in the 1980-2000 period celebrated by Mr. Siebel.

Declining growth rates over time are to be expected, Mr. Greenstein said. After all, it doesn’t take many sales to show huge percentage gains when the base is small.

TIMOTHY BRESNAHAN, a Stanford economist, similarly does not accept Mr. Siebel’s contention that the decline in growth rates this decade, which encompasses two recessions, signals a permanent end to I.T.’s record of growing faster than the larger economy. “It is early days to say the game is over,” he said.

When the economy recovers, there is no dearth of unfinished projects for I.T., he said, like “automating white-collar work and automating buying and selling in markets.”

And when one company dominates a certain area of technology, it can be a bottleneck along the road to innovation — an obstacle to the technology of others. Mr. Bresnahan says that this has happened with Microsoft in the PC side of corporate information technology, and in earlier times with I.B.M. in computers and AT&T in telecommunications. But he said that entrepreneurial companies of those earlier days — like Siebel Systems — ultimately invented around bottlenecks and “innovation-led growth picked up again.”

The biggest decline in I.T.’s growth came at the end of the 1960s, well before Mr. Siebel’s own I.T. career. A fortune or two could still be made, it turns out. Siebel Systems, which its founder says attained $2 billion in revenue annually in only seven years, was founded after the growth rate of I.T. spending dropped precipitously.

Entrepreneurial engineers in the United States should take heart. There’s no cause for mass flight to Shanghai.

Randall Stross is an author based in Silicon Valley and a professor of business at San Jose State University. E-mail: stross@nytimes.com.