Its great when you actually need to get shit done (see San Francisco), but rather terrible in the case you don't (see multiple empty million unit cities in China). In the very best case, this sort of spending is merely wasteful. I'm reminded of the crazy incentives in the Soviet Union.
EG, from SSC [1]
> A tire factory had been assigned a tire-making machine that could make 100,000 tires a year, but the government had gotten confused and assigned them a production quota of 150,000 tires a year. The factory leaders were stuck, because if they tried to correct the government they would look like they were challenging their superiors and get in trouble, but if they failed to meet the impossible quota, they would all get demoted and their careers would come to an end. They learned that the tire-making-machine-making company had recently invented a new model that really could make 150,000 tires a year. In the spirit of Chen Sheng, they decided that since the penalty for missing their quota was something terrible and the penalty for sabotage was also something terrible, they might as well take their chances and destroy their own machinery in the hopes the government sent them the new improved machine as a replacement. To their delight, the government believed their story about an “accident” and allotted them a new tire-making machine. However, the tire-making-machine-making company had decided to cancel production of their new model. You see, the new model, although more powerful, weighed less than the old machine, and the government was measuring their production by kilogram of machine. So it was easier for them to just continue making the old less powerful machine. The tire factory was allocated another machine that could only make 100,000 tires a year and was back in the same quandary they’d started with.
By the way, the cities are empty because they built them to be used later, and many are not empty anymore.
The Chinese government is slowly moving people from some places, to already built cities (while building other cities).
For now they can keep what they are doing, but I believe they will have to someday stop (otherwise they will build faster than the population increase), then is a matter of seeing how they will handle that stoppage.
But for now they have plenty of people to move, For example example the article here has a graph showing that in 2015 only 51% of the population is urban compare that to Brazil, Brazil is a country with a economy that relies on rural exports much more than china does, industry in Brazil is very weak, yet Brazil has 85% of the population being urban according to the World Bank, in some naive calculation, assuming China wants to match Brazil urbanization, this means they still have 462 million people to move... Projects like the one in the target aim to house 200.000 people, this mean they can do 2310 of such projects without wasting money on unused capacity.
EDIT: Running those numbers made me realize how China is mind-boggling huge and populated. China population that they intend to move, is bigger than Brazil + Russia summed population...
I did not mean to imply a motive to building a brand new, mostly empty city. Just that it's incredibly foreign, yet fascinating, and I can't imagine another country doing anything like that.
I would say, then, that it seems like this is a good idea so far!