] The Ind Rev brought had several fashion consequences, perhaps most notably the reduction of the cost of clothing, particularly cotton and wool. However, I can't think of why this should have contributed to plainness without getting very speculative.

I think among other things teh I Revolution brought the merchant classes mroe into society. they ewre not averse to show but they did nto want to spend hours on dressing powdering etc. So simpler fashions were more suitable...