They could even promote the dense urban clusters as "utopia" at first, attracting most of the populace. Once they are in, the conditions of the city would slowly deteriorate; but a population that was born in the city and never moved beyond a few blocks would just not know that there is anything better.
The current regime seems to be acutely aware of this and has been actively spreading Chinese influence (and finances) over the rest of the world.
There's a lot of mismanagement and climactic shifts in the pre-modern period. Often those are tied together, with failures of the hydrological infrastructure. But another common thread is high imbalances in male/female populations, leading to lots of disaffected young men, and millenarian religious movements.
[0] http://www.chinadaily.com.cn/a/201801/04/WS5a4d8db6a31008cf1...
With really good and fast transit I don't see a reason why we have to live physically near where we work though.