In the UK, a leaseholders get screwed if they forget to renew their lease before the 80 year mark.
The cost to develop the land needs to justify the development. If I spent $500k to build a house on the land, I would like to be able to use that house for as long as the house exists (or I sell it to re-coop the investment).
Many people are really bad at saving properly, but they will pay their mortgage. Landownership enables at least some old people to have a cushion in retirement.
You're mixing a house as personal property with the much broader claim of private property on land.
It is possible to protect those two uses you mentioned, and other reasonable uses of land, without at the same time spending state resources in enforcing perpetual, absolute, hereditary, exclusive titles on plots of land.