[jesterpm]

I assumed that the gap between the cost to do the bare minimum and the cost to do some elaborate was smaller at the time. If you're already laying each brick by hand, it seems like the incremental cost to work a pattern into the bricks would be small compared to modern (bland) poured-concrete buildings, where we lay a whole floor in one go. Likewise in other trades.

We invented machines to build large amounts of simple things cheaply, so we designed simpler things.