The problem with $/sq ft is that the land cost is bundled in. To get a true cost per square foot, you’d have to subtract the cost of the land first.
There is a fixed cost for having an entitled lot for one house, and anything larger does not increase in price at the same rate; for example, my house that I sold was on 5.2 acres, in an area zoned for 4 acre minimums. So the additional 1.2 acres was basically useless and had little additional value. Appraisers added $20K for each additional acre, so the parcel was probably valued at $330K for the land required to build a house (in this case 4 acres), and then $20K for each additional acre.
So an accurate $/sq ft requires knowing the underlying land costs, which is linear only beyond the minimum lot size need for constructing one home.
