i don't have data to back this up, but i'm sure the data is out there, given how meticulous the singapore government is with their planning:

- i can't imagine the government will elect to demolish and resell the land to a new developer in the majority of the housing stock as it comes due. therefore, many of the residents will get a pay-day at the end of the 99 year lease, which will soften the blow of the lease end.

- this is all already priced into the property you buy, and you're doing it with your eyes wide open. what determines the price of the property you buy? factors like: (1) the closer the property is to the 99 year mark (2) the more the run down it is [and therefore likely to be torn down] (3) whether or not the property makes sense given evolving zoning/use/density/purpose requirements.