Considering the range of weaponry available in D&D it could make sense. If you wanted to make it historically accurate you would have to remove weapons first since armor is a response to weapons. You'd also have to remove magic, and all the various magical creatures, so that battle tactics become more important. Otherwise buildings and castles would even look different, cause in a world with dragons and other flying nuisances and the ability of a magician to grant knights the ability to fly, castles would have developed full roofs much sooner.
All in all, I'm starting to think D&D just isn't meant to be historically accurate as presented in the book. It's up to the DM to pick a setting and decide how accurate it is. In other games with magic sometimes metal conducts magical energy and leather (especially made from tough creatures like dragons) and wooden armor become a lot more popular.
I think it's better to provide a full range of possible items and let the DM decide what is available.
