The land itself had to be acquired somehow. The very first owner paid for an army to take the land from the indigenous population that "owned" it, and that "cost" is a chain that is linked all the way to today (and at every step of the transaction, somebody profits by increasing the price a bit).
So either you raise another army today (at an even greater cost) to acquire the land, or you pay the asking price from the current owners.
It’s not just the acquisition of the land but also the investment in the economy that surrounds the land. All land starts out near worthless and in the middle of no where. Generations of sacrifice and investment are what turns it into a highly valuable property. That process can also reverse if the owner ceases to improve the property and invest in the community.
>All land starts out near worthless and in the middle of no where. //
No. People don't raise armies to steal land that's worthless. If you're going back to pre-history then the land near a nice river that has plenty of game, isn't predated by larger animals, and has nice fruit trees is worth way more to a person than some section of desert.
If right to live on land also goes with rights to exploit resources beneath the land then disparities in value as you approach the industrial era become massive.
There is a concept called "path dependence". Something may be important to get you from point A to point B, even if at point B you perhaps don't use it at all.
You start with a place with nice fruit trees near the river, then a few people build their houses there, then someone builds roads and a port, then someone builds larger houses, then someone builds factories... and at some moment in the future, there is a huge city, but the river is poluted and the trees were cut down.
There is another place with no trees and no river. Hundred years later, there is no city.
That's what Georgism is about: fully separating those two concepts. The land is valuable because of the community; the property is valuable because of its owner. So under Georgism, all land is held under common ownership, with the land's value being entirely taxed away from its occupier, allowing you to profit personally only by improving the property and supplying value to others thereby.
I do and I also respect others property rights. Communal ownership and responsibility should only cover those things for which there are no other options, even then they are hard enough to deal with.
Your initial claim was about the situation being just. This argument explains why and what situation we have, but you've done nothing to explain why it's just. "Raise another army or pay the price" is hardly a ringing endorsement of the fairness of the system.
The key thing to note is that this isn't the only model of land ownership possible. There are other that are more fair (land value taxes and community land trusts for example).
To be clear, I don't really have anything against individual landowners; it's the system that's unjust.
Much of the rent paid in big cities is not for the construction or maintenance costs, but the land value. Did the owner construct the land?