> It makes no sense for that value to be captured for all future time by a single owner, that just encourages pointless speculation and makes it harder to allocate real estate towards its highest and most valuable use.

How do 99 year leases fix the problem? Do people actually get kicked out at 99 years, or does the government renew it for a nominal fee?

The overwhelming majority of homes in Singapore are HDB flats built by the government. These are torn down and new, taller buildings fitting more people built in their place. It's called the Selective En-Block Redevelopment Scheme, or SERS[1]. People sell their flats to the government and are given new flats in other neighbourhoods, while their old homes are torn down and new ones rebuilt. So, yes, in some way, they are 'kicked out'.

[1]: https://www.hdb.gov.sg/residential/living-in-an-hdb-flat/ser...

If the lease gets renewed at market value then there's no point in speculating about what that land might be worth in the farther future. It's a key difference from a system where all of the future value must be captured at once by a single owner.