Unless your are Li Kai Shing or some other Hong Kong tycoon, you can afford to live in a house in Hong Kong island.
Land prices get more expensive than gold itself.
Hong Kong island, is roughly in its natural status, a big rock that emerges from the sea. The existent flat land is usually artificially "created" by reclamation.
Every buildable spot gets easily occupied:
The developers usually utilize the land occupation to its maximum capacity. A little more than just 25 m2 can give space to 80 apartments:
Hong Kong is one of the cities in the world with the highest population density (for reference only: 247,501 people per square mile - 20 times higher than India's).
In 1998, with the move of the old Hong Kong Airport from the Kowloon Peninsula to Check Lap Kok, the building height restriction was relaxed, from 20 to >80 floors.
Today, aiming as usual to utilize the land, there are residential buildings being built with 80 floors or more, giving the impression that the 20 floor-buildings nearby are just tiny little house.