90 year-olds may well have bought land at a bargain and would therefore suffer somewhat under an LVT. It's a transition problem though - since in the 100% LVT world the couple didn't have to work 50 years (and pay vast interest to a banker) to get that house.

19 year-olds on the other hand already compete with businesses for land (especially corporate landlords - who pay more than datacenter owners) and are losing rapidly.

You do lose the option of speculation - buy early before a town or region is built up. In the current system, speculation is not an option, it is compulsory.

Also you can't force everyone out of their houses - people could simply reserve land for residential purposes (as is already the case). It is still a democratic system, after all.

Finally, western governments already use eminent domain to repurpose land. It's already a part of our system.