Well if you had taken the time to read the article, you would know that they are offering this as a way of getting paid for doing real construction. The other option is getting paid in a single sum.

The tax route is not only better for the city's financing, it also means that if Google's vision isn't as successful, they get less money back. So they will be invested in making it succeed.

How do you think roads get built? The vast majority these sorts of projects are built by contractors, where the public largely just employs full-time workers for the design/finance side of things and then also maintenance.

Civil service rules make it very difficult for the government to hire people for limited periods of time. What would the government do with highway construction workers after the job was done? Sure there might be another project three states away, but it’s not reasonable to tell workers they have to move every few years.