Yet this amazing success story isn’t actually making any profit, even at such scale; instead, it’s losing billions, including $5 billion in one particularly costly quarter. After 10 years of growth, it has smashed the old business model of its industry, weakened legacy competitors and created value for consumers — but it has done all this using the awesome power of free money, building a company that would collapse into bankruptcy if that money were withdrawn. And it has solved none of the problems keeping it from profitability: The technology it uses isn’t proprietary or complex; its rival in disruption controls 30 percent of the market; the legacy players are still very much alive; and all of its paths to reduce its losses — charging higher prices, paying its workers less — would destroy the advantages that it has built.

So it sits there, a unicorn unlike any other, with a plan to become profitable that involves vague promises to somehow monetize all its user data and a specific promise that its investment in a different new technology — the self-driving car, much ballyhooed but as yet not exactly real — will make the math add up.

That’s the story of Uber — so far. It isn’t an Instagram fantasy or a naked fraud; it managed to go public and maintain its outsize valuation, unlike its fellow unicorn WeWork, whose recent attempt at an I.P.O. hurled it into crisis. But it is, for now, an example of a major 21st-century company invented entirely out of surplus, and floated by the hope that with enough money and market share, you can will a profitable company into existence. Which makes it another case study in what happens when an extraordinarily rich society can’t find enough new ideas that justify investing all its stockpiled wealth. We inflate bubbles and then pop them, invest in Theranos and then repent, and the supposed cutting edge of capitalism is increasingly defined by technologies that have almost arrived, business models that are on their way to profitability, by runways that go on and on without the plane achieving takeoff.

Do people on your coast think all this is real? When the tech executive asked me that, I told him that we did — that the promise of Silicon Valley was as much an article of faith for those of us watching from the outside as for its insiders; that we both envied the world of digital and believed in it, as the one place where American innovation was clearly still alive. And I would probably say the same thing now because, despite the stories I’ve just told, the internet economy is still as real as 21st-century growth and innovation gets.

But what this tells us, unfortunately, is that 21st-century growth and innovation are not at all what we were promised they would be.

III.

The decadent economy is not an impoverished one. The United States is an extraordinarily wealthy country, its middle class prosperous beyond the dreams of centuries past, its welfare state effective at easing the pain of recessions, and the last decade of growth has (slowly) raised our living standard to a new high after the losses from the Great Recession.