Land will always be scarce because it isn't quantity of land (though that too can be a separate issue) but quantity coupled with positioning of land. Most people could afford to purchase four acres of land in Alaska or VT's north east kingdom, but four acres along central park is quite expensive because, due to the location of the site relative to all the services of NYC and the access to greenery, it is rather exclusive... and I don't believe (including references from all the SciFi I've ever read) that there is any situation society could be in that would nullify the difference in value of two parcels of land - Judge Dredd and Mega City one I believe come closest, even though land overall is much more of a limited supply, most of the inhabitable land is equally worthless - but there are still a few Oasis of dystopian high society around that have vastly different value.

If we draw even to Hitchiker's Guide's concept of built planets, and we considered the cost of making planets would eventually trend to zero... there is still the concept of locality that would influence price.

Presumably, if you have unlimited resources, you can create most, if not all, of what makes that land in NYC valuable. You could create enough city districts to meet demand.

There's lots of factors that go into the value of land. Available amenities, jobs, being near other people, quality of schools and other resources, transportation, etc. But those all seem to boil down to scarce resources being pooled in one area. If you could mass produce amenities, buildings, school supplies, etc, then NYC wouldn't have any inherent value, because its equal would exist everyone someone cared to plop one down where there was enough demand to fill it with people.

I don't know if post-scarcity must mean perpetual motion machine. I'm not certain if you're familiar with the societal concept of systems collapse but it may be that attempting to do that would result in a maintenance burden that's untenable... Also I think a large chunk of NYC's value is in its people and I believe there's always going to be advantageous positioning from rarity, maybe this eventual society still has a government that has a capitol building and people congregate specifically around that... or perhaps it's more artificial - if the whole world was a city perhaps it'd get less significant and value would come from living at exactly 0' 0' or 3'14" 15'92" and so on.

I think there's a bit of innate petty jealousy in human beings so land value differentials will always exist.

But, that angle is pretty thin, so maybe I'm just stretching the argument at this point. Quite interesting to ponder!

I think that the problem is that the time when technology causes dramatic unemployment is likely to happen long before the time when technology can provide unlimited resources. So the question is: what do we do in-between?

The idea of land ownership is as mythical as Thor's hammer. You don't own land - you own a right to do certain things on that land to the exclusion of others. Only sovereignty gives actual ownership of land - transferring it to another jurisdiction, setting up your own laws, destroying said land and doing whatever the fuck one would do when one is literally "law onto oneself".

Also - money is no longer representative of a thing you can hold. Money is a share of wealth of a nation, which includes trust, culture, people, land and buildings.

How is land ownership different from anything else, say like the Thors hammer I bought on ebay?

It seems to me that colonizing other planets would only be a viable solution if we first developed faster than light or at least near light speed travel; and those may or may not be physically possible. Otherwise we would just end up with a scarcity of planets within practical travel distance of each-other.

Not really. Even if we triple land use efficiency, population growth will increase the demand to compensate

Not at current fertility rates. If the current trend continues we're in for a world-wide population decline.

Other replies addressed the issues with assuming that population growth will continue as-is, but I also wanted to mention that humans are pretty creative so if we did continue to grow we'd likely start doing ecumenopolis things, deepening ocean trenches to concentrate oceans more and increase the usable land area on earth, start seriously considering the moon/mars for terraforming, building more vertically (above and below ground).

I don't think the volume of land will ever be an issue for humans, but I think that land will never be equally valued.

If you increase education, you'll learn that population will not grow that fast.

Population growth has been steadily slowing down since 1960s.

Broadly speaking, that is because we're approaching something like a carrying capacity, estimated to be somewhere around 10B.

If we increase land use efficiency dramatically, that effectively raises the carrying capacity and population growth can continue much longer

The population growth decline is not tied to the carrying capacity but to the development of the economy. Countries that are further economically developed have lower birth rates and vice versa. For example Finland is mostly a country of deserted forest, yet it has a very slow growth rate. The country could carry a population of 50 million easily, but is hardly growing anymore at 5 million.