I don't think they're saying that the cities are overbuilt in the short term but could be overbuilt in the long term. It can take decades for a large apartment

I don't think they're saying that the cities are overbuilt in the short term but could be overbuilt in the long term. It can take decades for a large apartment building to show an ROI. A significant decline in renters, even over 10-15 years can leave large development projects without the money to maintain the buildings and grounds. Gross looking buildings of course struggle even more to attract renters and a neighborhood can go into a downward spiral in as little as a decade.