That incentive already exists, landholders typically use their land in a high-value way. If you cast your eye on Europe there are a large contingent of undeserving people who have generations of wealth that they secure through owning land, which does not degrade over time. The big win of a land tax is about breaking ultra-low-risk inter-generational wealth transfer. If wealth is transferred between generations there at least has to be some level of competent management demonstrated by each new layer of the family tree.
The same principle seem to apply to LVT: A landowner would, it seems, be forced, by the taxes extracted from them, to generate a matching (or larger) income by the land, regardless if they might feel that the community would be better served by using the land for something which would, incidentally, make less money for them personally.
If the object of LVT is to prevent inter-generational wealth transfer, I would assume that there would be vastly more effective ways to accomplish this more directly. Or there could at least be some carve-out which limits the effect of a LVT to those instances.
> ... regardless if they might feel that the community would be better served by using the land for something which would, incidentally, make less money for them personally ...
The community obviously disagrees with our landholder in this scenario, or the community can stump up the cash to pay the land taxes or hold the land publically.
It is just 1 more expense. It isn't like running a soup kitchen was ever free, someone is paying for the soup. Giving a donation of space is the same as giving a donation of time and materials.
There are incentives, but there isn't anything especially new here. It isn't going to be radically different from a mortgage in the short term, and in the long term the change is competent people will own land instead of old families.
The rest of your text can be summarized as “whoever has money deserves to have it, and should be trusted to make decisions which override any community which, in aggregate, have less money”. I believe this to be a somewhat controversial stance.
But that's theoretically. Whether you could actually impose this regime is a different matter. What the "real" value of land isn't a clear thing thing imo. A town might that since it's zoning prevents building much, it's land isn't worth much.