When Apple unveiled its new gadget Tuesday, it wasn’t the much-hoped-for iPhone 5. But many pointed to Siri, the new voice-activated personal assistant in the iPhone 4S, as proof Apple had again redefined the way we use phones. It’s talking, not typing, from here on out.

Apple's Senior Vice President of Worldwide product marketing Phil Schiller introduces voice-activated personal assistant “Siri.” (Kevork Djansezian/GETTY IMAGES)

“Seriously doesn't innovation seem lopsided? We can crank out new iPhones but not like, new trains,” Robin Sloan of Twitter wrote Wednesday. “Apple has basically built us the U.S.S. Enterprise's computer. BUT WHERE IS THE ENTERPRISE.”

It’s been an increasing worry for the technology-obsessed for years.

Science fiction writer Neal Stephenson recently wrote a piece for the World Policy Institute in which he compared the lack of big innovations today with the creation in his parents and grandparents generation of the airplane, the automobile, nuclear energy and the computer, as well as explorations in space.

“I worry that our inability to match the achievements of the 1960s space program might be symptomatic of a general failure of our society to get big things done,” Stephenson wrote.

Stephenson is not alone. Many worry that as the U.S. builds new gadgets and shuts down its manned space missions, China is building bullet trains and launching its first space lab.

Others wonder why we are still so oil-dependent when we have been talking about wind farms, tidal power and solar power for years.

Was the computer really the last big life-changing creation? Surely, a voice-activated personal assistant can’t be all our innovators have got.

PayPal co-founder and Facebook investor Peter Thiel criticized Silicon Valley last month as lacking “companies that represent genuine progress.” Instead, the companies simply chase the latest fashion. He said innovation was between “dire straits and dead.”

Stephenson names three reasons he thinks we have been unable to execute on big stuff in this generation:

1. As science and technology become more complex, researchers and engineers have found themselves focused on more narrow topics, meaning they tackle just a slice of the pie.

2. As in the case of manned space missions, politics has increasingly come into the equation.

3. In a world that looks increasingly unstable and dangerous, we’ve stopped accepting risks. We can Google any new idea and find out whether it’s already been executed or failed.

“The imperative to develop new technologies and implement them on a heroic scale... [is] the only way for the human race to escape from its current predicaments,” Stephenson writes. “Too bad we’ve forgotten how to do it.”

It may be that those current predicaments are too comfortable for some.

Francisco Dao, the founder of 50Kings, which hosts invitation-only adventures for technology and media innovators, wrote in the Post last month: “As Plato said, it is ‘necessity who is the mother of invention.’ In the developed world, are there really any necessities?”

He cites airplane innovation as hitting a plateau in the 1970s with the arrival of pressurized cabins and jet engines. Dao recommends people seek moral imperatives — not self-interest — as a motivation to create.

Perhaps, though, it is not a question of whether or not we innovate, but of whether we recognize advancements in a century crammed full of them. Comedian and writer Louis C.K., for one, thinks we no longer respect the innovations we only recently made. In a famous speech, C.K. chastises people for complaining about airplane seats that don’t recline.

“What happened then?” he asks. “Did you fly through the air like a bird, incredibly? Did you soar into the clouds, impossibly? Did you partake in the miracle of human flight and then land softly on giant tires?”