It gets more costly over time. There's not much that can be done to increase the efficiency of building a stone wall, except for prefab when it's possible. All other goods become cheaper to produce so the stone mason becomes more and more expensive in comparison. At least to some degree, the same principle applies to education and health care.

I find it fascinating that the result of this effect is that it's unlikely to be able to build a high quality brick house ever again. Most brick houses today are just wood frames with prefab brick cladding. The brick row house tenements of 1910 are now the million dollar condos of 2010.