Due to low supply and high demand prices are high.  As a rapidly growing country, Hong Kong consists of 7,482 million people as of 2020. From Planning Department of Hong Kong, 75.6% of Hong Kong’s land is non built area and 24.3% of it is developed land. However, only 3.7% of the developed land is urban housing. Hong Kong has no issue with land supply itself, much more so about land usage.

Hong Kong’s Developed Land v.s Natural Land (Business Insider 2021)

But why is land not getting used?
The short and simple answer is the government controls all the land in Hong Kong.
Hong kong’s government leases out its land to developers for the highest bid. The reason why government leases out its land is because the majority of the government’s income comes from the leases. The thing is the developer who leases the land either doesn’t do anything with the land or builds their own establishment for their own reason. With more and more land getting leased there is less land for housing and providing more funded housing for people will lower the government’s income.

Who gets affected?
People who are most affected are every class, even the billionaires. The lower class are forced to either be homeless or live in the “coffin houses.” The middle class makes too much money for public housing and doesn’t have enough to buy making them self-independent to struggle. Billionaires play a monopoly with the land but with the scarcity of land, prices of land keep increasing every year.