Nobody ever did. Hardwood is completely impractical to build a house with. You'd have to predrill a hole for every nail. Also, nominal dimensions have always r

Nobody ever did. Hardwood is completely impractical to build a house with. You'd have to predrill a hole for every nail. Also, nominal dimensions have always referred to the as-sawn size: planed size has always been smaller by the amount of planing since small-dimension stock began to be used 120-140 years ago. The only difference is that the actual (smaller) size varied widely between sawmills until the early 1960s, when the finished size was regulated.