As mentioned, those areas all need several years to become ready for sale, or for amenities to gather sufficient scale to build residential on a large scale. Paya Lebar airbase is still in use and should be fully ready around 2030. The Greater Southern Waterfront port is clearing but still has many infrastructure running till 2030, after which amenitisation will commence.
https://www.straitstimes.com/singapo...-air-base-gone
"The relocation of Paya Lebar Air Base from 2030 will free up 800ha of land - bigger than Bishan or Ang Mo Kio. Current height restrictions in the eastern swathe of Singapore to ensure navigational safety for aircraft will be relaxed, meaning that current low-rise buildings may be redeveloped."
https://www.ura.gov.sg/Corporate/Pla...s/Central-Area
"Greater Southern Waterfront
The planned relocation of the City Terminals and Pasir Panjang Terminal to Tuas will free up 325 and 600 hectares of waterfront land respectively. With the first set of berths at Tuas Port to be operational by 2025, the downtown and southern port area will eventually be phased out. This area is known as the Greater Southern Waterfront.
With about 1,000 hectares of land – an area three times the size of Marina Bay - up for development in the Greater Southern Waterfront after 2030, the landscape we can paint is limited only by our imagination. As we stand at the threshold of a new chapter in our city’s development, we would like to share six broad ideas for the Greater Southern Waterfront with you. The possibilities are immense and we would like to hear your ideas for our waterfront of the future."
In the meantime, there is a need to slow down release of private land tremendously. Not much readily/immediately available plots left in the next 10 years.