Blame the millennials.

Those gadget-wielding young people born in the 1980s and 1990s are the reason America's real-estate market seems, well, a bit confused.

After decades of suburban sprawl designed to accommodate the nation's love affair with its cars, millennials and "the creative class" want something else — a walkable place to live, said Christopher Leinberger, an urban strategist and researcher who visited York this week.

That demand for urban life — where people can live, work and play within a relatively small geographic area — is both driving and slowing the economic recovery these days, Leinberger said.

The message from millennials today: "We're not going to put up with this boring place."

Complex: Meeting that demand requires more complex solutions than, say, building a strip mall in the suburbs.

"It takes a much more organic approach to make it happen," Leinberger said.

But if government officials and private developers can work out the details and find ways to finance revitalization, cities like York are well positioned to capitalize on millennials' desire for higher-density living, he said.

And this is no fashion trend, Leinberger said.

"The economy's demanding it," he said.

Leinberger, who has visited York several times over the past decade, was the keynote speaker Thursday at the York County Community Foundation's annual meeting.

He met with reporters Thursday afternoon to talk about nationwide trends and his impressions of York.

Reversal: Decades ago, Americans largely abandoned their cities for the suburbs.

"Now they're coming back," Leinberger said. "We're over-built drivable suburban. We have pent-up demand for walkable urban."

Figuring out how to meet demand with supply is the challenge, he said.

The stakes are high for cities like York, Leinberger said.

"If you don't offer the market what it wants, it's going to go somewhere else," he said.

Leinberger said he first visited York about 10 years ago. He found a "pretty shabby little place" downtown.

Clearly, he said, things are turning around.

Yorkers are smart to focus on the Codorus Creek and York College as anchors of revitalization. He also complimented the role of Downtown Inc as a "place manager."

He said revitalization requires leadership from government officials willing to bring talented people to the table.

"Then they have to stand back and say, 'Let the private sector go forward,'" Leinberger said.