Why is renting instead of buying a house more cost-effective in Sydney?

Sydney's housing prices are roughly around 55,000. But renting a place here costs about 20,000 per month. Compared to China, the value for renting is far less compared to buying. If we go by the logic of 55,000 per square meter, theoretically, rent should be around 10,000 per month. So, why does this imbalance exist?