Bob Mannix wrote:

snip

I had reason to look into the value of a ransom strip some 20 years ago
and the advice then was the owner could hold out for as much as half the
expected profit from the landlocked land.

Eh? The owner could hold out for twice the expected profit if they wanted -
they wouldn't get it but there isn't a limit!

You know what I meant. :-)

It's his land to sell or not for whatever price he wants.

Everyone seems to be under the misapprehension that land (and houses) have
an intrinsic value. As things stand, in this country, it is as close to a
free market as you can get (although not perfect as Dr D will point out).
The value of land is entirely extrinsic and is "whatever someone is willing
to pay"!

Taking your argument to its logical extreme only money has an intrinsic
value. Everything else is worth what someone else is prepared to pay for it.

With run-of-the-mill houses as with second hand cars there is a general
consensus as to their approximate worth. With vanity items such as Old
Master paintings the value is largely determined by the amount of
surplus cash available for disposal and the reputation of the object on
offer.

In between there may be some items that are a 'must have' to an
individual who will pay through the nose to purchase but are of little
or no interest to the rest of use but as I see it the case in question
revolves around the interests of just 2 parties, the owners of the
properties involved. Neither actually needs the deal but in this case
the seller is the one with the whip hand which is why the deal has more
chance of being concluded if the buyer accepts that the seller deserves
a fair share of the potential profit.