Wow. Well, for the first time, I am officially embarrassed for you. Those are not the words of a businessman or an economist, and you are so far off on this this one it's pathetic. Rather having me go out and Google things for you, why not just post and cite a couple of your favorite and most authoritative examples? Because you have inventory and supply reversed, along with a seriously distorted and incorrect view of market supply and how it is counted.
If you did any actual Googling yourself, you would see myriad examples that define supply as:
"The total quantity of a good or service that is available for purchase
at a given price."
http://economics.about.com/od/supply/p/supply.htm
Not at any price; at any
given, or
specified, price. In economics you can't even begin to talk about supply without a specific reference price in mind. From there we can take all possible prices and make a supply curve for that particular thing. If a thing is not for sale at a given price it is not counted as part of the "supply available to the market"
at that price.
The owner's decision not to sell at a given price is precisely what EXCLUDES it from being counted as available to the market (supply)
at that price. You are attempting to count the aggregate total of a thing in existence that
might possibly otherwise be available AT ANY POSSIBLE PRICE (or at any possible time in the future) and calling that "the entire supply available to the market". That is absolutely incorrect. That's how a supply curve is created, NOT how supply itself is counted.
So to rephrase your words so that they read accurately:
"Being already in someone's possession does not mean a thing is no longer part of the supply. In economics the determining factor as to whether or not a thing is counted as part of the available supply is the price the owner would be willing to accept - and this is true for all goods and services in a free market - a price that is somewhere between zero and infinity. Above a given price, it may be counted as part of the supply. Below that same given price it may not be counted as part of the available supply. This price, and not mere possession, is the very basis of the supply curve in economics, upon which curve multiple quantities of the same thing can be theoretically plotted."
Since actual supply available to the market is dependent upon the quantity sellers are willing to part with
for a given price, supply is plotted as
individual coordinates on a supply curve, the plot points of which are specified reference prices -- not the entire curve, not the maximum supply possible on that curve, and not the aggregate total based on the possibility that any of it could sell if the price was high enough.
Whatever sellers will not part with at a given price, for ANY REASON,
is not counted on that part of the curve as part of the supply for that price. That includes land that is publicly or privately withheld from the market at a given price
for any reason whatsoever -- even if the reason for withholding it from sale is not related to price.
If you have an economist, economics paper or textbook entry that states otherwise, cite the source, as I would very much like to read it. Show me otherwise. Don't tell me, using your own rationale and trying to pass that off as basic economics. Show me. Arguments backed by actual sources.
I'll answer your other post after we settle this once and for all. Good luck.