Land rights is an interesting subject, one of the foundations of society and fought over since man roamed the earth. For some, land belongs to the people while for others land can be purchased and owned by individuals. You can see where that's going...
Singapore juggles freehold (you own the land and whatever you build on it) and leasehold (usually 99 years).
For example, the estate we live in is considered an old estate, built in the mid 80s. It's a 99 years leasehold, due to be handed back to the state in 2088, a which point owners will be compensated based on that year's property value.
Every 3 years the HOA can vote to enblock the property, meaning 80% of homeowners agree to sell the estate to a developer (usually at above market value based on years of ownership) and get priority buying a new unit on the new estate at discount). The inconvenience is having to find a place to live for the 3-5+ years it takes to build the new estate and is the reason it's not easy to reach 80% agreement.
On the other hand, property value depreciates as the 2088 deadline approaches and buyers avoid the hassle of buying a unit in a building expected to come down.
What it comes down to is retirees want to spend their remaining years in their unit and don't want to enblock while younger owners want to sell their unit for an added profit and get a new unit at discount to either live in or sell.