I never entirely understood Georgism's focus on land value rather than capital in general.

Surely owning a factory is capturing the benefits of productivity just as much as owning the land it stands on?

Building a factory is a social contribution. More generally factories are (usually) subject to the normal laws of supply and demand: if they get too expensive, people can build more, if there are too many people can convert them into housing etc.

(if we have a fixed supply of factories e.g. because of zoning laws then it could become a case of economic rents. But the simple solution there is "don't do that then")