Because otherwise ... yeah? Private toll roads can be a good solution.
The city simply made an analysis of the number of roads they'd build over the years and the cost of being a capable engineering organization versus the premium of getting existing experts to build it. They probably don't generate their own electricity either, for the same reasons.
The only reason they sell it off is to make cash now for whatever political reason at the expense of future taxpayers.
The delivery of electricity is also handled by governments, or companies that are basically government since they have to run everything by governments first like price increases. Just like water lines and sewer lines. Electricity generation does not need to be government operated since it can come from multiple sources, but the delivery is just like roads since you can’t have multiple options to each destination.
Generally, but I could plan to have that contractor back for each repair as long as they do a good job.
> The state has allowed NTTA to have a lifetime contract of earning tolls on the roads even past the cost of building those roads
Presumably they're responsible for maintaining the roads. We've simply decided to call them for repairs as long as they do a good job.
> The contractor does not keep sending you bills after the fees have been paid
If I defer up-front costs in trade for maintenance costs then they do. This is really handy some times.