I don't see how you can get stiffed while ending up with a good piece of road to drive on.
Really? Let me see if I can explain it in simple terms.
The minister in charge of public works proposes to company X that they build a toll road.
Minister of Public Works: Hey, I could give you a license to build a toll road from A to B and would expect a nice kickback from you.
Company X: Nah. There would never be enough traffic to make it profitable.
MPW: Oh, come on! how am I going to get a kickback then?
CX: Why don't you build the road yourself and stop bothering me?
MPW: No. That would not work. I would have to get the expense approved in the national budget and that would never pass because, you know, it would never be profitable. I tell you what. You propose an unrealistic forecast of traffic that makes it profitable and we guarantee that if you don't get that traffic we would compensate you.
CX: Oh, OK. That way we cannot lose money.
Company X builds the road which, surprise, surprise, does not have enough traffic to make it profitable. A big debacle ensues when it is found out the State would have to pay money to the greedy company. All negative public opinion is directed against greedy, unscrupulous company X. But company X got what they contracted for, the corrupt government officers got their kickbacks and the public got screwed because they paid for a road that was not worth building in the first place and has much less traffic than "predicted". If realistic traffic projections had been considered the road would not have been considered worth building.
And it is not only roads. There are many other constructions in the same situation. Buildings, airports, bridges, etc which sit idle and have no use whatsoever. Yeah, the public paid for an airport and got an airport. ... which was not needed and which now has no use.
If you can't see how that is getting stiffed, well, I don't know what to say.
The same thing happened with the second Panama Canal. A Spanish Company was the lowest bidder outbidding an American company. Everybody said it was impossible to do it for that price but Spain wanted the contract and the Spanish government guaranteed it. Well, dontcha know it, they said it couldn't be done and the Spanish company found out it couldn't be done. Then nobody wanted to take responsibility. The company said it had found unexpected geological problems, the Spanish government said it would rather not pay. I don't know how it was resolved in the end but I assume it was the usual way: another round of kickbacks to everyone involved.
Just because the taxpayer paid for a [road, bridge, airport, etc.] and that was built and delivered does not mean the taxpayer got their money's worth.
https://en.wikipedia.org/wiki/Gravina_Island_BridgeDo you understand it now? Or would a diagram help?