You make a good point, but a modern day blade of high quality is able to hold a sharper edge. The older blades may have originally had a steeper bevelled edge, and that edge was removed long ago and reformed more than once. Ancient blades become dull with time and use, so the blade becomes narrower every time a new edge is introduced, and that would be for the polisher at any given time to take the liberty and freedom of style to accomplish a desired edge. So if that were done today, it would be no more than a recurring procedure.