[imtringued]

>How does this mechanism work in concrete terms? My understanding is that Georgism advocates raising taxes on people with property in desirable locations. They decide they can't afford the taxes, so they sell to a developer, who tears down the house and builds a bigger building.

You have a 500m^2 plot of land. This plot pays $50k land value taxes. If one person lives on the land that person pays the full tax. If 10 people live on the property they each pay $5k taxes per year. If 50 live there then the tax is $1k.

Property taxes scale with the building so housing more people means higher taxes. That is being avoided by only taxing the land.

Alternatively, people hate taxes, they want to avoid paying taxes. If you want to avoid land value taxes, the only way to do that is to use less land more efficiently.