Such voices were all but drowned out this week at Nanotech 2004, the industry's largest conference.
And why not? The economy is rebounding, investors are interested, and last year President Bush signed a bill to invest nearly $3.7 billion for nanotech research in the coming years.
Attendance tripled over last year, organizers said, reflecting a maturing industry. The inaugural conference seven years ago was a small gathering of lab rats; now it's as much a trade show as a science meeting, with real companies setting up booths.
"If you listen to a lot of the VCs, they'll say (nanotechnology) is still a science project," said Steven Currall, director of a Rice University program that supports business activities by researchers. "A lot of them say it's 10 years in the future. They're nuts. It's not 10 years."
Nanotechnology is the science of manipulating the tiniest units of matter, and making use of the unusual properties many substances exhibit at these almost incomprehensible scales: no larger than a billionth of a meter, or 1/100,000th the diameter of a hair.
Researchers in chemistry, physics, and biology are already touting progress on projects that could someday lead to highly affordable solar energy or microscopic robots that attack bacteria and cancer cells.
But a closer look at this week's conference also revealed why some are still skeptical--at least in the short run.
The 90 companies that bought booths at the conference trade show was a threefold increase in just three years. But many of the companies make the instruments that nanotechnology labs use to do other things--"pick and shovels for the miners in the gold rush" in the words of one venture capitalist.
Many attention-getting companies in the field are still laying the groundwork for the future.
Richardson, Texas-based Zyvex is researching ways to build materials from single molecules, but for now makes instruments and materials. Inmat, of Hillsborough, N.J., hopes its nanocomposite coating will eventually be used in tires and chemical defense products, but for now it's being used to add bounce to Wilson tennis balls.
Another big challenge: manufacturing what the researchers invent.
"It's one thing to be able to do this in a lab where you're just pushing molecules around," said Donald Bansleben, a program manager with the National Institute of Standards and Technology, which will be partly responsible for handing out federal research grants. Take, for example, carbon nanotubes. These tiny hexagons have unusual properties and could someday be used in microscopic electronic devices, but making them on a large scale may be a headache as far into the future as can be imagined.
One difficulty is that molecules act strangely at such small scales, which makes them potentially useful but also difficult to manipulate. And the scale is so small that nano-devices will likely have to be made by the billions or trillions to be useful. Normal manufacturing methods will be useless. Nanosystems will have to build themselves.
"You have to use things like replication or evolution or self-assembly or self-repair," said Warren Packard, a Silicon Valley venture capitalist who has invested in the field. "We need to figure out how to grow systems versus build systems."
Another big topic this week was the anticipated flood of federal money. Universities are eager to be sure, but several noted that it will mean the United States is only now pulling even with Japan in supporting nanotechnology.
On Wednesday, the California Institute of Technology announced it had received a $7.5 million grant to start a nanoscience center.
Proponents insist that, overall, nanotechnology is too broad, too important and too obviously useful to fail. Commercially, it will be better insured by real products and intellectual property than were previous technology fads.
But they know there will be bumps.
"I'm a near-term optimist and a long-term optimist but a mid-term pessimist," said Lynn Foster, who advises companies in the field. "It's not the next big thing. It's several of the next things after the next big thing."