I have said this before, but I see some parallels between the modern world and Japan during the early Tokugawa era. Japan had pretty much reached a steady state by the time Tokugawa Iyeyasu came to power in 1600; most of the available land had been cultivated or settled, and, especially after the policies of Toyotomi Hideyoshi, society was locked in a rigid structure without much room for advancement or unrest. As a…
Basically the Japanese government funds a large number of "pointless" projects, such as freeways to nowhere, large sea-facing cement walls, or things like subsidizing construction companies and the like (this is why you'll see 6 people standing around a hole in the ground, 3 "bosses" doing absolutely nothing, 2 of them old men flagging traffic, 1 person doing the actual digging). This is how Japan manages to keep their unemployment rate low, and thus keep money moving through the economy - by making sure people are able to obtain a job, even if it's useless or redundant.
At the top of it all you have the massive Zaibatsu (big conglomerates) which fund the lower level companies under their umbrella which in turn pay these meager salaries and keep people employed, typically as some kind of tax write off and the side benefits of having all of these various companies at their disposal (concrete, construction, real estate, etc).
The bottom of the system is incredibly inefficient, but it helps make sure that a bare minimum quality of life is available for people willing to try to get any old job.
Interesting article which sums up big infrastructure projects and their long term drawbacks/benefits better than I can (2009) - https://www.nytimes.com/2009/02/06/world/asia/06japan.html