It is the case now that it is profitable to purchase a rundown building, pay the property taxes for years, and then sell it for a significantly higher value. T

It is the case now that it is profitable to purchase a rundown building, pay the property taxes for years, and then sell it for a significantly higher value. This is the rent seeking behavior that a Land Value Tax seeks to eliminate. By taxing the unimproved value of land, it becomes more and more burdensome to sit and do nothing with your property. By making improvements (building a high rise, running a productive farm, etc.) you reduce your tax burden and, as you mentioned, profit from the improvements. So a more productive and efficient land use is encouraged by land value tax compared to property taxes which since they are based on total value (including improvements) you could potentially be punished for being more productive than just doing nothing.