Liz, ever counted the number of bloody buttons on a 17th Century cassock? Imagine doing the best part of 200 buttons and buttonholes by hand!
Took me bloody ages when I was about 19, but it made me the man I am today (blind, with swollen fingers and a yearning for zips and velcro!). And, Fibula, for most living history devotees, the maxim is "give me authenticity or give me death". As Lynn states, its only by wearing the clothes in the way they were worn, eating the food, sleeping on the bedding and - just sometimes - enduring the lice, ticks and other parasites that allows us fully to connect.
That said, there's a fair number of tossers in all re-enactment groups whose sole aim is to get as pissed as possible and have a punch-up, but they're the minority and in some parts have almost died out - perhaps to be replaced by the authenticity pedants...