Trump’s rhetoric may also lead nowhere. But the focus on the immediate political question of whether it does or doesn’t masks how profoundly the philosophy about how to build and maintain America’s stuff has shifted. The amount of money private equity and other finance outfits have amassed in preparation for an anticipated infrastructure boom testifies to it. Preqin, which collects data on the industry, now counts 84 infrastructure-oriented funds around the world that have each raised at least $1 billion in capital. Not all of this dry powder is designated for use in the U.S., of course, but the most highly publicized recent fund announcement, a deal between Blackstone and the government of Saudi Arabia, shows the hoped-for scale. The Saudis agreed to invest a reported $20 billion into a $40-billion Blackstone U.S. infrastructure fund. In all, Blackstone has plans to invest a total of $100 billion into U.S. works.

Even armed with such a cash payload, private-equity financiers, just as they do when they buy a company, do not typically buy a bridge, or road, or waterworks outright. They often create a separate entity for each project. Then they take a small amount out of their pool of cash, and have the project-specific entity borrow the rest from banks, or they sell bonds that will pay interest to investors in return for using their money. Money to pay those investors, so goes the idea, comes from revenue generated later on by the project.

For example, Spain’s Grupo Isolux Corsán Finance created Isolux Infrastructure Netherlands B.V., which in turn formed I-69 Development Partners to build a part of Interstate 69 in Indiana during the administration of then-Governor Mike Pence. Isolux put down $40.5 million of its own investors’ money and sold $252 million in bonds. That $252 million in debt has proven to be too much. The project was running out of money, subcontractors were going unpaid, and default seemed imminent, so the state of Indiana was forced to take over the project and issue its own bonds.

Something similar happened in San Diego County, and to a road in Texas. Approved in 2006, the Texas 130 toll road was supposed to be completed by Cintra, another Spanish infrastructure builder, through an entity it created called SH 130 Concession Company. In March of last year, SH 130 filed for Chapter 11 bankruptcy. According to a story in the San Antonio Express-News, “the road already is showing signs of persistent pavement problems. And a residential part of Lockhart, the small town on the route known for barbecue, has experienced more severe floods since it opened.”

Whether it’s P3s, or the outright privatization of public assets, as Trump suggests doing with the air-traffic control system, cautionary tales abound. Many experts cite the case of Chicago, which sold off its parking meters to a consortium headed by Morgan Stanley and including the government of Abu Dhabi.* The consortium paid the city $1.1 billion. The Chicago Sun-Times estimated that the consortium will earn back its investment from meter revenue three years from now, but the deal runs for another 60 years. So Morgan Stanley, Abu Dhabi, and the other partners will pocket millions every year ($156 million in 2015) from Chicago parkers. Meanwhile, the city has to pay the consortium every time it takes a meter out of service—during a street fair, for example. As The New York Times explored last December, cities can be blindsided by such deals, especially if a private owner raises the price, for example, of using its water system in order to provide a profit to investors.