Depending on the model, private capital is engaged in both the short term and the long term. If you're in a long-term arrangement, because a P3 can be just a matter of design, build, and finance through construction, in that world, if they're building a piece of an extension to a subway line and you're not paying them until it's built, they have to raise the capital and put their money at risk to pay to build that line. If you're engaging them in a long-term arrangement, which includes design, build, operate, and maintain, you keep their capital at risk over the whole life of the asset, so that at any time, if you're not satisfied that they're meeting the performance expectations set out in the contract, you stop paying them.
It's not just that they're losing the opportunity; they're going to be losing their capital, and they're not going to be able to pay back the people they borrowed the money from. That's not just a matter of having a bad deal with the government. That means putting their whole company at risk, and this is serious. That private capital brings serious discipline to the execution of these projects.