The house you mentioned (San Marcos) after reductions is still listing at $196/sqft. The one I am getting in Maybeck comes out to be $188/sq ft. And, did I mention…the house also has ~$20K+ upgrades (granite in kitchen & master bath, fireplace & few other things)
In regards to the house shown on zillow (2000 built, $640K), I am assuming the owner got some $60K-$70K upgrades as the usual price at that time was ~$550K-$570K for a similar sized home.
These posts have been really helpful. So, keep them coming.