I did allude to that in a previous comment regarding the "propping up "and "weighing down" of values
> Lower cost is not necessarily lower value. Land cost is land rental value times some amount of time (usually based on the expected cap rate).
Cap rate/land rental value is difficult to assess on land
> There are, for instance, empty parcels of land in Idaho that now go for more than whole apartment buildings in Detroit Are the two parcels the same size? Are they representative of surrounding parcels and not outliers? Are they the same distance (in transit time/cost) as the nearest town/city center?
I'll admit that I don't have the exact values under the constraints you've listed. And given different geographies, that's going to be difficult to accomplish. However, there have been several reports of prices in Idaho increasing due to now-former residents of the Bay Area fleeing into state and buying up land and houses.
https://www.krem.com/amp/article/news/local/out-of-state-hom...
...which is already subtracted out along with the rest of the improvements' contribution to land values. You could argue that it ain't a perfectly accurate subtraction - and that'd be a valid and reasonable argument - but that margin of error cuts both ways (i.e. overestimating improvement value instead of underestimating it).
> Lower cost is not necessarily lower value.
Land cost is land rental value times some amount of time (usually based on the expected cap rate).
> There are, for instance, empty parcels of land in Idaho that now go for more than whole apartment buildings in Detroit
Are the two parcels the same size? Are they representative of surrounding parcels and not outliers? Are they the same distance (in transit time/cost) as the nearest town/city center?