> No, landlords
do not provide land.
They provide access to their land, which is the same thing. This debate is not about who (or what) created the physical dirt. It is about the economic value of the property, which only exists as a result of human action.
> as evidenced by the fact that you are calling the land good or bad prior to having been developed by the landlord
You misread. The land is known to be good or bad in retrospect. At the time it was developed that classification was only speculative. This particular landlord thought the land would be good and thus worth developing. Others disagreed and didn't bid as highly for it. The landlord is rewarded not for others' efforts but for the fact that they were right when they predicted that this would be a good location for their development.
> All the gains generated by improvements upon the land – or enhancements in the "usability" of the land – will be retained by the landlord.
To the best approximation either of us will be able to come up with that is 100% of the market value of the land. However, you are speaking in terms of ideals. In practice only the cost of building physical structures on the land will be counted as "improvement". There is no need to guess; this is the legal standard which is already applied in the rare situations where improvements must be valued separately from the land. However, it severely understates the property owners' contributions to the overall value.
> More importantly, it is a disincentive to speculating on that land (or withholding it from the market/withholding it from productive use).
The fact that you fail to see the economic value of speculation is a depressingly common failing among LVT supporters. Putting land to a lower-value use now prevents it from being put to a higher-value use later, which destroys wealth. Speculation holds the land ready for the higher-value use, which is why it is rewarded.
Here's a hypothetical example: Say there's a plot of land which could be used for either warehousing or family homes. If you simply put it up for auction right now for a term of perhaps 50 years you'll get $100M from the warehouse representatives or $80M from family home developers. Whichever way you go you'll be locked in to that use for at least 50 years. However, trends show that the warehouse industry is in a decline, whereas demand for family homes in that area will likely increase to $150M within ten years—meaning that if you just take the highest offer now then you will be losing out on $50M of value and those families won't have enough homes. In the best case there will be a significant cost incurred to demolish the warehouses and rebuild. The correct answer here is to speculate based on the trends that a higher-value use will come along and allow only short-term, non-destructive uses of the property in the interim rather than auctioning it off immediately. Or even leave it vacant for a few years if there are no such uses.